#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<ll> llv1;
ll N;
ll ans;
ll mn(ll a, ll b) {
return a < b ? a : b;
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> N;
ans = 2 * (N + 1);
for(int i = 2; i * i <= N; i++) {
int k = N / i;
if(N % i > 0) k += 1;
ans = mn(ans, (i + 1) * (k + 1));
}
cout << ans;
}