func_code_string: #include <bits/stdc++.h>   using namespace std;   int s[18257 + 1];   int main() {     memset(s, 0, sizeof(s));     s[1] = 1;     for (int i = 2; i <= 18257; i++) {       s[i] = (2 * i - 3) * 6 + 6;     }     int a;     scanf( %d , &a);     if (a == 1) {       cout << s[1] << endl;     } else {       int sum = 0;       for (int i = 1; i <= a; i++) {         sum += s[i];       }       cout << sum << endl;     }     return 0;   }   