func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     unsigned long long int n, ans, i, j, k;     cin >> n;     if (n == 0) {       cout <<  1  << endl;       return 0;     }     ans = 2 * n * n;     ans = ans + ((n + 2) * (n + 1)) - 1;     cout << ans << endl;     return 0;   }   