import core.bitop;
import std.algorithm;
import std.ascii;
import std.bigint;
import std.conv;
import std.functional;
import std.math;
import std.numeric;
import std.range;
import std.stdio;
import std.string;
import std.random;
import std.typecons;
import std.container;

ulong MOD = 1_000_000_007;
ulong INF = 1_000_000_000_000;
alias sread = () => readln.chomp();

void main()
{
    auto n = lread();
    auto f = n.factorization();
    // f.writeln();
    long mincost = INF;
    foreach(i; iota(f.length))
    {
        long cost = f[i] + f[$ - 1 - i];
        mincost = min(cost, mincost);
    }
    writeln(mincost - 2);
}

T lread(T = long)()
{
    return readln.chomp.to!T();
}

T[] aryread(T = long)()
{
    return readln.split.to!(T[])();
}

void scan(TList...)(ref TList Args)
{
    auto line = readln.split();
    foreach (i, T; TList)
    {
        T val = line[i].to!(T);
        Args[i] = val;
    }
}

auto factorization(long a)
{
    auto factor = new long[](0);
    auto limit = cast(long) sqrt(cast(float) a);
    foreach (i; iota(limit))
    {
        long tmp = i + 1;
        if (a % tmp == 0)
        {
            factor ~= tmp;
            if (tmp != a / tmp)
                factor ~= a / tmp;
        }
    }
    factor.sort();
    return factor;
}
