#include <bits/stdc++.h>   using namespace std;   int main() {     int n, s = 0;     cin >> n;     if (n >= 1 && n <= 100) {       if (n == 1)         cout << 1;       else {         while (1) {           if (n == 2) {             s = s + 5;             break;           }           s = s + (n * 2) + (n - 2) * 2;           n = n - 1;         }         cout << s;       }     }   }   