/+ dub.sdl:
    name "A"
    dependency "dcomp" version=">=0.8.0"
+/

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

// import dcomp.array, dcomp.container.deque, dcomp.dungeon;

int main() {
    Scanner sc = new Scanner(stdin);
    int H, W, k;
    sc.read(H, W, k);
    string[] g = new string[H];
    foreach (i; 0..H) sc.read(g[i]);
    auto sv = g.findFirst2D('S');

    int[][] dist = iota(H).map!(_ => (10^^9).repeat.take(W).array).array;
    bool[][] vis = new bool[][](H, W);
    Deque!(int[2]) q;
    q.insertBack(sv);
    dist.at2D(sv) = 0;
    int ans = 10^^9;
    while (q.empty == false) {
        auto p = q.front; q.removeFront;
        if (vis.at2D(p)) continue;
        vis.at2D(p) = true;
        int di = min(p[0], H-1-p[0], p[1], W-1-p[1]);
        ans = min(ans, 1+(di+k-1)/k);
//        writeln(p, di);
        if (dist.at2D(p) == k) break;
        foreach (np; p.neighbors4(Dungeon(H, W))) {
            if (g.at2D(np) == '#') continue;
            if (dist.at2D(np) <= dist.at2D(p) + 1) continue;            
            dist.at2D(np) = dist.at2D(p) + 1;
            q.insertBack(np);
        }
    }
    writeln(ans);
    return 0;
}
/* IMPORT /home/yosupo/Program/dcomp/source/dcomp/dungeon.d */
// module dcomp.dungeon;

 
immutable static int[2][4] direction4 = [
    [0, 1], [1, 0], [0, -1], [-1, 0],
];
 
immutable static int[2][8] direction8 = [
    [0, 1],
    [1, 1],
    [1, 0],
    [1, -1],
    [0, -1],
    [-1, -1],
    [-1, 0],
    [-1, 1],
];

static int[2] addInt2(in int[2] a, in int[2] b) {
    int[2] c;
    c[] = a[] + b[];
    return c;
}

 
struct Dungeon {
     
    static int[2] move4(int[2] p, int dir) {
        return addInt2(p, direction4[dir]);
    }
     
    static int[2] move8(int[2] p, int dir) {
        return addInt2(p, direction8[dir]);
    }


    immutable int R, C;
     
    this(int R, int C) {
        this.R = R;
        this.C = C;
    }
     
    bool isInside(int[2] p) const {
        int r = p[0], c = p[1];
        return 0 <= r && r < R && 0 <= c && c < C;
    }
     
    int getID(int[2] p) const {
        int r = p[0], c = p[1];
        return r*R+c;
    }
}


auto neighbors4(int[2] p) {
    static struct Rng {
        int[2] center;
        size_t i;
        bool empty() const { return i == 4;}
        int[2] front() const { return addInt2(center, direction4[i]); }
        void popFront() { i++; }
    }
    return Rng(p, 0);
}

auto neighbors4(int[2] p, in Dungeon dg) {
    static struct Rng {
        int[2] center;
        Dungeon dg;
        size_t i;
        this(in int[2] center, in Dungeon dg) {
            this.center = center;
            this.dg = dg;
            while (!empty() && !dg.isInside(front)) i++;
        }
        bool empty() const { return i == 4;}
        int[2] front() const { return addInt2(center, direction4[i]); }
        void popFront() {
            i++;
            while (!empty() && !dg.isInside(front)) i++;
        }
    }
    return Rng(p, dg);
}
/* IMPORT /home/yosupo/Program/dcomp/source/dcomp/container/stackpayload.d */
// module dcomp.container.stackpayload;

 
struct StackPayload(T, size_t MINCAP = 4) if (MINCAP >= 1) {
    import core.exception : RangeError;

    private T* _data;
    private uint len, cap;

    @property bool empty() const { return len == 0; }
    @property size_t length() const { return len; }
    alias opDollar = length;

     
    inout(T)[] data() inout { return (_data) ? _data[0..len] : null; }
    
    ref inout(T) opIndex(size_t i) inout {
        version(assert) if (len <= i) throw new RangeError();
        return _data[i];
    }  
    ref inout(T) front() inout { return this[0]; }  
    ref inout(T) back() inout { return this[$-1]; }  

    void reserve(size_t newCap) {
        import core.memory : GC;
        import core.stdc.string : memcpy;
        import std.conv : to;
        if (newCap <= cap) return;
        void* newData = GC.malloc(newCap * T.sizeof);
        cap = newCap.to!uint;
        if (len) memcpy(newData, _data, len * T.sizeof);
        _data = cast(T*)(newData);
    }  
    void free() {
        import core.memory : GC;
        GC.free(_data);
    }  
     
    void clear() {
        len = 0;
    }

    void insertBack(T item) {
        import std.algorithm : max;
        if (len == cap) reserve(max(cap * 2, MINCAP));
        _data[len++] = item;
    }  
    alias opOpAssign(string op : "~") = insertBack;  
    void removeBack() {
        assert(!empty, "StackPayload.removeBack: Stack is empty");
        len--;
    }  
}

 
/* IMPORT /home/yosupo/Program/dcomp/source/dcomp/scanner.d */
// module dcomp.scanner;

// import dcomp.container.stackpayload;

 
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 {
                StackPayload!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 /home/yosupo/Program/dcomp/source/dcomp/container/deque.d */
// module dcomp.container.deque;

struct DequePayload(T) {
    import core.exception : RangeError;

    private T* _data;
    private uint start, len, cap;

    @property bool empty() const { return len == 0; }
    @property size_t length() const { return len; }
    alias opDollar = length;

    ref inout(T) opIndex(size_t i) inout {
        version(assert) if (len <= i) throw new RangeError();
        if (start + i < cap) return _data[start + i];
        else return _data[start + i - cap];
    }
    ref inout(T) front() inout { return this[0]; }
    ref inout(T) back() inout { return this[$-1]; }

    void reserve(size_t newCap) {
        import core.memory : GC;
        import std.algorithm : max;
        import std.conv : to;
        if (newCap <= cap) return;
        T* newData = cast(T*)GC.malloc(newCap * T.sizeof);
        foreach (i; 0..length) {
            newData[i] = this[i];
        }
        _data = newData; start = 0; cap = newCap.to!uint;
    }
    void clear() {
        start = len = 0;
    }
    import std.algorithm : max;
    void insertFront(T item) {
        if (len == cap) reserve(max(cap * 2, 4));
        if (start == 0) start += cap;
        start--; len++;
        this[0] = item;
    }
    void insertBack(T item) {
        if (len == cap) reserve(max(cap * 2, 4));
        len++;
        this[len-1] = item;
    }
    void removeFront() {
        assert(!empty, "Deque.removeFront: Deque is empty");
        start++; len--;
        if (start == cap) start = 0;
    }
    void removeBack() {
        assert(!empty, "Deque.removeBack: Deque is empty");        
        len--;
    }
}

 
struct Deque(T, bool mayNull = true) {
    import core.exception : RangeError;
    import std.range : ElementType, isInputRange;
    import std.traits : isImplicitlyConvertible;

    alias Payload = DequePayload!T;
    Payload* _p;
    
    static if (!mayNull) @disable this();

     
    this(U)(U[] values...) if (isImplicitlyConvertible!(U, T)) {
        _p = new Payload();
        foreach (v; values) {
            insertBack(v);
        }
    }
     
    this(Range)(Range r)
    if (isInputRange!Range &&
    isImplicitlyConvertible!(ElementType!Range, T) &&
    !is(Range == T[])) {
        _p = new Payload();
        foreach (v; r) {
            insertBack(v);
        }
    }
    private this(Payload* p) { _p = p; }
    static Deque make() { return Deque(new Payload()); }
    
    private bool havePayload() const { return (!mayNull || _p); }    
    @property bool empty() const { return (!havePayload || _p.empty); }  
    @property size_t length() const { return (havePayload ? _p.length : 0); }  
    alias opDollar = length;  

    ref inout(T) opIndex(size_t i) inout {
        assert(!empty, "Deque.opIndex: Deque is empty");
        return (*_p)[i];
    }  
    ref inout(T) front() inout { return this[0]; }  
    ref inout(T) back() inout { return this[$-1]; }  

    void clear() { if (_p) _p.clear(); }  

     
    void insertFront(T item) {
        if (mayNull && !_p) _p = new Payload();
        _p.insertFront(item);
    }
    void insertBack(T item) {
        if (mayNull && !_p) _p = new Payload();
        _p.insertBack(item);
    }  
    alias opOpAssign(string op : "~") = insertBack;  
    alias stableInsertBack = insertBack;  

     
    void removeFront() {
        assert(!mayNull || _p, "Deque.removeFront: Deque is empty");
        _p.removeFront();
    }
    void removeBack() {
        assert(!mayNull || _p, "Deque.removeBack: Deque is empty");
        _p.removeBack();
    }  
    alias stableRemoveBack = removeBack;  

     
    alias Range = RangeT!(DequePayload!T);
    alias ConstRange = RangeT!(const DequePayload!T);  
    alias ImmutableRange = RangeT!(immutable DequePayload!T);  

    size_t[2] opSlice(size_t dim : 0)(size_t start, size_t end) const {
        assert(start <= end && end <= length);
        return [start, end];
    }  
    Range opIndex(size_t[2] rng) { return Range(_p, rng[0], rng[1]); }  
    ConstRange opIndex(size_t[2] rng) const { return ConstRange(_p, rng[0], rng[1]); }  
    ImmutableRange opIndex(size_t[2] rng) immutable { return ImmutableRange(_p, rng[0], rng[1]); }  
    auto opIndex() inout { return this[0..$]; }  

    static struct RangeT(QualifiedPayload) {
        alias A = QualifiedPayload;
        import std.traits : CopyTypeQualifiers;
        alias E = CopyTypeQualifiers!(A, T);
        A *p;
        size_t l, r;

        @property bool empty() const { return r <= l; }
        @property size_t length() const { return r - l; }
        alias opDollar = length;

        @property auto save() { return this; }
        
        ref inout(E) opIndex(size_t i) inout {
            version(assert) if (empty) throw new RangeError();
            return (*p)[l+i];
        }
        @property ref inout(E) front() inout { return this[0]; }
        @property ref inout(E) back() inout { return this[$-1]; }

        void popFront() {
            version(assert) if (empty) throw new RangeError();
            l++;
        }
        void popBack() {
            version(assert) if (empty) throw new RangeError();
            r--;
        }
        
        size_t[2] opSlice(size_t dim : 0)(size_t start, size_t end) const {
            assert(start <= end && end <= length);
            return [start, end];
        }
        auto opIndex(size_t[2] rng) { return RangeT(p, l+rng[0], l+rng[1]); }
        auto opIndex(size_t[2] rng) const { return RangeT!(const A)(p, l+rng[0], l+rng[1]); }
        auto opIndex(size_t[2] rng) immutable { return RangeT!(immutable A)(p, l+rng[0], l+rng[1]); }
        auto opIndex() inout { return this[0..$]; }
    } 
}

 
 

 

 

 

 

 

 
/* IMPORT /home/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);
            }
        }
    }
     
}
/* IMPORT /home/yosupo/Program/dcomp/source/dcomp/array.d */
// module dcomp.array;

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

 
 

 
int[2] findFirst2D(T, U)(in T mp, in U c) {
    import std.conv : to;
    int R = mp.length.to!int;
    int C = mp[0].length.to!int;
    foreach (i; 0..R) {
        foreach (j; 0..C) {
            if (mp[i][j] == c) return [i, j];
        }
    }
    assert(false);
}

 
 

 
auto ref at2D(T, U)(ref T mp, in U idx) {
    return mp[idx[0]][idx[1]];
}

 
 

/*
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)
*/
