#include <bits/stdc++.h>   using namespace std;   int triangle(long long n) {     if (n == 1)       return 1;     else       return n + triangle(n - 1);   }   int heart(long long a) {     if (a == 1)       return 1;     else       return (6 * (a - 1)) + heart(a - 1);   }   int balls(long long a) {     if (a == 1)       return 1;     else       return heart(a) + (triangle(a - 1) * 6);   }   int main() {     long long a, b;     cin >> a;     b = balls(a);     cout << b;     return 0;   }   