51nod 最小周长

#include<iostream>
#include<algorithm>
#include<vector>
#include<cstring>
#include<cstdio>
#include<cmath>
using namespace std;
typedef long long LL;
#define MAXN 1001
#define INF 0x3f3f3f3f
LL solve(LL n)
{
    LL m = INF,t;
    LL a = (LL)sqrt((double)n);
    LL d = a*a>n? -1:1;
    t=a;
    while(n%t)
    {
        t+=d;
    }
    return (t+n/t)*2;
}
int main()
{
    LL n;
    cin>>n;
    cout<<solve(n)<<endl;
    return 0;
}