/+ dub.sdl:
    name "A"
    dependency "dcomp" version=">=0.7.1"
+/

import std.stdio, std.algorithm, std.range, std.conv, std.math;
// import dcomp.foundation, dcomp.scanner;
// import dcomp.datastructure.segtree;

immutable L = 10^^8;

double solve(int sx, int sy, int tx, int ty, int[2][] p) {
    assert(sx != tx && sy != ty);

    int[] v = [sy, ty] ~ p.map!"a[1]".array;
    v = v.sort!"a<b".uniq.array;
    int getI(int x) {
        return v.assumeSorted.lowerBound(x).length.to!int;
    }


    auto M = v.length.to!int;
    auto seg = SimpleSeg!(int, (a, b) => max(a, b), -(10^^9))(M);
    seg[0] = 0;
    foreach (d; p) {
        int py = getI(d[1]);
        seg[py] = seg[0..py+1].sum() + 1;
    }
    int c = seg[0..M].sum();
    double off = (tx-sx + ty-sy) * 100.0;
    off += c * (-20.0 + 5*PI);
    if (c == 1+min(tx-sx, ty-sy)) {
        off += 5*PI;
    }
    return off;
}

int main() {
    Scanner sc = new Scanner(stdin);
    int sx, sy, tx, ty;
    sc.read(sx, sy, tx, ty);
    int n;
    sc.read(n);
    int[2][] p = new int[2][n];
    foreach (i; 0..n) {
        sc.read(p[i][0], p[i][1]);
    }
    if (sx > tx) {
        sx = L - 1 - sx;
        tx = L - 1 - tx;
        foreach (i; 0..n) {
            p[i][0] = L - 1 - p[i][0];
        }
    }
    if (sy > ty) {
        sy = L - 1 - sy;
        ty = L - 1 - ty;
        foreach (i; 0..n) {
            p[i][1] = L - 1 - p[i][1];
        }
    }
    if (sx == tx) {
        swap(sx, sy);
        swap(tx, ty);
        foreach (i; 0..n) {
            swap(p[i][0], p[i][1]);
        }
    }
    p = p.filter!(a =>
        sx <= a[0] && a[0] <= tx &&
        sy <= a[1] && a[1] <= ty).array;
    p.sort!"a[0] < b[0]";
    debug {
        writeln(sx, " ", sy, " ", tx, " ", ty);
        writeln(p);
    }
    if (sy == ty) {
        double r = (tx - sx) * 100.0;
        if (p.length) {
            r -= 20;
            r += 10 * PI;
        }
        writefln("%.20f", r);
        return 0;
    }
    writefln("%.20f", solve(sx, sy, tx, ty, p));
    return 0;
}
/* IMPORT /Users/yosupo/Program/dcomp/source/dcomp/scanner.d */
// module dcomp.scanner;

// import dcomp.array;

 
class Scanner {
    import std.stdio : File;
    import std.conv : to;
    import std.range : front, popFront, array, ElementType;
    import std.array : split;
    import std.traits : isSomeChar, isStaticArray, isArray; 
    import std.algorithm : map;
    File f;
    this(File f) {
        this.f = f;
    }
    char[512] lineBuf;
    char[] line;
    private bool succW() {
        import std.range.primitives : empty, front, popFront;
        import std.ascii : isWhite;
        while (!line.empty && line.front.isWhite) {
            line.popFront;
        }
        return !line.empty;
    }
    private bool succ() {
        import std.range.primitives : empty, front, popFront;
        import std.ascii : isWhite;
        while (true) {
            while (!line.empty && line.front.isWhite) {
                line.popFront;
            }
            if (!line.empty) break;
            line = lineBuf[];
            f.readln(line);
            if (!line.length) return false;
        }
        return true;
    }

    private bool readSingle(T)(ref T x) {
        import std.algorithm : findSplitBefore;
        import std.string : strip;
        import std.conv : parse;
        if (!succ()) return false;
        static if (isArray!T) {
            alias E = ElementType!T;
            static if (isSomeChar!E) {
                 
                 
                auto r = line.findSplitBefore(" ");
                x = r[0].strip.dup;
                line = r[1];
            } else static if (isStaticArray!T) {
                foreach (i; 0..T.length) {
                    bool f = succW();
                    assert(f);
                    x[i] = line.parse!E;
                }
            } else {
                FastAppender!(E[]) buf;
                while (succW()) {
                    buf ~= line.parse!E;
                }
                x = buf.data;
            }
        } else {
            x = line.parse!T;
        }
        return true;
    }
    int read(T, Args...)(ref T x, auto ref Args args) {
        if (!readSingle(x)) return 0;
        static if (args.length == 0) {
            return 1;
        } else {
            return 1 + read(args);
        }
    }
}


 
 

 
/* IMPORT /Users/yosupo/Program/dcomp/source/dcomp/array.d */
// module dcomp.array;

 
T[N] fixed(T, size_t N)(T[N] a) {return a;}

 
 

 
struct FastAppender(A, size_t MIN = 4) {
    import std.algorithm : max;
    import std.conv;
    import std.range.primitives : ElementEncodingType;
    import core.stdc.string : memcpy;

    private alias T = ElementEncodingType!A;
    private T* _data;
    private uint len, cap;
     
    @property size_t length() const {return len;}
    bool empty() const { return len == 0; }
     
    void reserve(size_t nlen) {
        import core.memory : GC;
        if (nlen <= cap) return;
        
        void* nx = GC.malloc(nlen * T.sizeof);

        cap = nlen.to!uint;
        if (len) memcpy(nx, _data, len * T.sizeof);
        _data = cast(T*)(nx);
    }
    void free() {
        import core.memory : GC;
        GC.free(_data);
    }
     
    void opOpAssign(string op : "~")(T item) {
        if (len == cap) {
            reserve(max(MIN, cap*2));
        }
        _data[len++] = item;
    }
     
    void insertBack(T item) {
        this ~= item;
    }
     
    void removeBack() {
        len--;
    }
     
    void clear() {
        len = 0;
    }
    ref inout(T) back() inout { assert(len); return _data[len-1]; }
    ref inout(T) opIndex(size_t i) inout { return _data[i]; }
     
    T[] data() {
        return (_data) ? _data[0..len] : null;
    }
}

 
 
/* IMPORT /Users/yosupo/Program/dcomp/source/dcomp/datastructure/segtree.d */
// module dcomp.datastructure.segtree;

import std.traits;

struct SegTree(alias E, Args...) {
    import std.conv : to;
    import std.traits : ReturnType;
    alias Engine = E!Args;
    alias T = Engine.DataType;
    alias L = Engine.LazyType;
    Engine eng;
    this(uint n) {
        eng = Engine(n);
    }
    this(T[] first) {
        eng = Engine(first);
    }
    @property size_t length() const { return eng.length(); }
    @property size_t opDollar() const { return eng.length(); }
    struct Range {
        Engine* eng;
        size_t start, end;
        @property T sum() {
            return eng.sum(start.to!uint, end.to!uint);
        }
    }
    const(T) opIndex(size_t k) {
        assert(0 <= k && k < eng.length());
        return eng.single(k.to!uint);
    }
    void opIndexAssign(T x, size_t k) {
        assert(0 <= k && k < eng.length());
        eng.singleSet(k.to!uint, x);
    }
    size_t[2] opSlice(size_t dim)(size_t start, size_t end) {
        assert(0 <= start && start <= end && end <= eng.length());
        return [start, end];
    }
    Range opIndex(size_t[2] rng) {
        return Range(&eng, rng[0].to!uint, rng[1].to!uint);
    }
    static if (!is(L == void)) {
        void opIndexOpAssign(string op : "+")(L x, size_t[2] rng) {
            eng.add(rng[0].to!uint, rng[1].to!uint, x);
        }
    }
}

 
template LazySeg(T, L, alias opTT, alias opTL, alias opLL, T eT, L eL, alias Engine = LazySegEngine) {
    import std.functional : binaryFun;
    alias LazySeg = SegTree!(Engine, T, L,
        binaryFun!opTT, binaryFun!opTL, binaryFun!opLL, eT, eL);
}

 
 

 
template SimpleSeg(T, alias opTT, T eT, alias Engine = SimpleSegEngine) {
    import std.functional : binaryFun;
    alias SimpleSeg = SegTree!(Engine, T, binaryFun!opTT, eT);
}

 
 


struct LazySegEngine(T, L, alias opTT, alias opTL, alias opLL, T eT, L eL) {
    import std.typecons : Tuple;
    alias DataType = T;
    alias LazyType = L;
    alias S = Tuple!(T, "d", L, "lz");
    uint n, sz, lg;
    S[] s;
    this(uint n) {
        import std.conv : to;
        import std.algorithm : each;
        this.n = n;
        uint lg = 0;
        while ((2^^lg) < n) lg++;
        this.lg = lg;
        sz = 2^^lg;
        s = new S[](2*sz);
        s.each!((ref x) => x = S(eT, eL));
    }
    this(T[] first) {
        import std.conv : to;
        import std.algorithm : each;
        n = first.length.to!uint;
        uint lg = 0;
        while ((2^^lg) < n) lg++;
        this.lg = lg;
        sz = 2^^lg;

        s = new S[](2*sz);
        s.each!((ref x) => x = S(eT, eL));
        foreach (i; 0..n) {
            s[sz+i].d = first[i];
        }
        foreach_reverse (i; 1..sz) {
            update(i);
        }
    }
    @property size_t length() const { return n; }
    pragma(inline):
    private void lzAdd(uint k, in L x) {
        s[k].lz = opLL(s[k].lz, x);
        s[k].d = opTL(s[k].d, x);
    }
    private void push(uint k) {
        if (s[k].lz == eL) return;
        lzAdd(2*k, s[k].lz);
        lzAdd(2*k+1, s[k].lz);
        s[k].lz = eL;
    }
    private void update(uint k) {
        s[k].d = opTT(s[2*k].d, s[2*k+1].d);
    }
    T single(uint k) {
        k += sz;
        foreach_reverse (uint i; 1..lg+1) {
            push(k>>i);
        }
        return s[k].d;
    }
    void singleSet(uint k, T x) {
        k += sz;
        foreach_reverse (uint i; 1..lg+1) {
            push(k>>i);
        }
        s[k].d = x;
        foreach (uint i; 1..lg+1) {
            update(k>>i);
        }
    }
    T sum(uint a, uint b) {
        assert(0 <= a && a <= b && b <= n);
        if (a == b) return eT;
        a += sz; b--; b += sz;
        uint tlg = lg;
        while (true) {
            uint k = a >> tlg;
            if (a >> tlg != b >> tlg) {
                tlg++;
                break;
            }
            if (((a-1) >> tlg) + 2 == (b+1) >> tlg) return s[k].d;
            push(k);
            tlg--;
        }
        T sm = eT;
        foreach_reverse (l; 0..tlg) {
            uint k = a >> l;
            if ((a-1)>>l != a>>l) {
                sm = opTT(s[k].d, sm);
                break;
            }
            push(k);
            if (!((a >> (l-1)) & 1)) sm = opTT(s[2*k+1].d, sm);
        }
        foreach_reverse (l; 0..tlg) {
            uint k = b >> l;
            if (b>>l != (b+1)>>l) {
                sm = opTT(sm, s[k].d);
                break;
            }
            push(k);
            if ((b >> (l-1)) & 1) sm = opTT(sm, s[2*k].d);
        }
        return sm;
    }
    void add(uint a, uint b, L x) {
        assert(0 <= a && a <= b && b <= n);
        if (a == b) return;
        a += sz; b--; b += sz;
        uint tlg = lg;
        while (true) {
            uint k = a >> tlg;
            if (a >> tlg != b >> tlg) {
                tlg++;
                break;
            }
            if (((a-1) >> tlg) + 2 == (b+1) >> tlg) {
                lzAdd(k, x);
                foreach (l; tlg+1..lg+1) {
                    update(a >> l);
                }
                return;
            }
            push(k);
            tlg--;
        }
        foreach_reverse (l; 0..tlg) {
            uint k = a >> l;
            if ((a-1)>>l != a>>l) {
                lzAdd(k, x);
                foreach (h; l+1..tlg) {
                    update(a >> h);
                }
                break;
            }
            push(k);
            if (!((a >> (l-1)) & 1)) lzAdd(2*k+1, x);
        }
        foreach_reverse (l; 0..tlg) {
            uint k = b >> l;
            if (b>>l != (b+1)>>l) {
                lzAdd(k, x);
                foreach (h; l+1..tlg) {
                    update(b >> h);
                }
                break;
            }
            push(k);
            if ((b >> (l-1)) & 1) lzAdd(2*k, x);
        }
        foreach (l; tlg..lg+1) {
            update(a >> l);
        }
    }
}


struct SimpleSegEngine(T, alias opTT, T eT) {
    alias DataType = T;
    alias LazyType = void;
    import std.functional : binaryFun;
    uint n, sz, lg;
    T[] d;
    @property size_t length() const {return n;}
    this(uint n) {
        import std.algorithm : each;
        uint lg = 0;
        while ((2^^lg) < n) lg++;
        this.n = n;
        this.lg = lg;
        sz = 2^^lg;
        d = new T[](2*sz);
        d.each!((ref x) => x = eT);
    }
    this(T[] first) {
        import std.conv : to;
        import std.algorithm : each;
        n = first.length.to!uint;
        if (n == 0) return;
        uint lg = 0;
        while ((2^^lg) < n) lg++;
        this.lg = lg;
        sz = 2^^lg;
        d = new T[](2*sz);
        d.each!((ref x) => x = eT);
        foreach (i; 0..n) {
            d[sz+i] = first[i];
        }
        foreach_reverse (i; 1..sz) {
            update(i);
        }
    }
    pragma(inline):
    private void push(uint k) {}
    void update(uint k) {
        d[k] = opTT(d[2*k], d[2*k+1]);
    }
    T single(uint k) {
        return d[k+sz];
    }
    void singleSet(uint k, T x) {
        k += sz;
        d[k] = x;
        foreach (uint i; 1..lg+1) {
            update(k>>i);
        }
    }
    T sum(uint a, uint b) {
        assert(0 <= a && a <= b && b <= n);
        T sml = eT, smr = eT;
        a += sz; b += sz;
        while (a < b) {
            if (a & 1) sml = opTT(sml, d[a++]);
            if (b & 1) smr = opTT(d[--b], smr);
            a >>= 1; b >>= 1;
        }
        return opTT(sml, smr);
    }
}

 


 



 
/* IMPORT /Users/yosupo/Program/dcomp/source/dcomp/foundation.d */
// module dcomp.foundation;
 
static if (__VERSION__ <= 2070) {
    /*
    Copied by https://github.com/dlang/phobos/blob/master/std/algorithm/iteration.d
    Copyright: Andrei Alexandrescu 2008-.
    License: $(HTTP boost.org/LICENSE_1_0.txt, Boost License 1.0).
    */
    template fold(fun...) if (fun.length >= 1) {
        auto fold(R, S...)(R r, S seed) {
            import std.algorithm : reduce;
            static if (S.length < 2) {
                return reduce!fun(seed, r);
            } else {
                import std.typecons : tuple;
                return reduce!fun(tuple(seed), r);
            }
        }
    }
     
}
version (X86) static if (__VERSION__ < 2071) {
    import core.bitop : bsf, bsr, popcnt;
    int bsf(ulong v) {
        foreach (i; 0..64) {
            if (v & (1UL << i)) return i;
        }
        return -1;
    }
    int bsr(ulong v) {
        foreach_reverse (i; 0..64) {
            if (v & (1UL << i)) return i;
        }
        return -1;   
    }
    int popcnt(ulong v) {
        int c = 0;
        foreach (i; 0..64) {
            if (v & (1UL << i)) c++;
        }
        return c;
    }
}

/*
This source code generated by dcomp and include dcomp's source code.
dcomp's Copyright: Copyright (c) 2016- Kohei Morita. (https://github.com/yosupo06/dcomp)
dcomp's License: MIT License(https://github.com/yosupo06/dcomp/blob/master/LICENSE.txt)
*/
