#include<bits/stdc++.h>
#include "testlib.h"
using std::cin;
using std::cout;
using std::endl;
using ll = long long;

int main(){
    registerValidation();
    ll max = 1e9;
    ll K = inf.readLong(1,max,"K");
    ll ans = 4*K*K+2;
    cout << ans << endl;
    inf.readEoln();
}