#include<iostream>
#include<vector>
using namespace std;
int fr(int k){
    for (long long i = k; i >= 0; --i){
        if (i*i <= k) return i;
    }
}
int main(){
    int n; cin >> n; int f = fr(n); //cout << fr(n) << endl;
    if (n - f*f == 0) cout << 4*f;
    else if (n - f*f == 1) cout << 4*f + 2;
    else if (n - f*f > 1 && n - f*f < f + 1) cout << 4*f + 2;
    else if (n - f*f == f + 1) cout << 4*f + 4;
    else if (n - f*f > f + 1 && n - f*f <= 2*f + 1) cout << 4*f + 4;
    else if (n - f*f == 2*f + 2) cout << 4*f + 6;
    else if (n - f*f > 2*f + 2 && n - f*f <= 3*f + 2) cout << 4*f + 6;
    else if (n - f*f == 3*f + 3) cout << 4*f + 8;
    else cout << 4*f + 8;

}