func_code_string: #include <bits/stdc++.h>   using namespace std;   template <typename Tp>   inline void outarr(Tp _begin, Tp _end, const char* _delim =    ) {     for (Tp current = _begin; current != _end; ++current) {       std::cout << *current << _delim;     }     std::cout <<   n ;   }   using ll = int64_t;   using pii = std::pair<int, int>;   constexpr int INF = 0x3f3f3f3f;   constexpr int MOD = static_cast<const int>(1e9 + 7);   int F(int x) {     if (x == 1) {       return 1;     }     return 12 * (x - 1);   }   int main() {     std::ios_base::sync_with_stdio(false);     std::cin.tie(nullptr);     int a;     cin >> a;     ll ans = 0;     for (int i = 1; i <= a; ++i) {       ans += F(i);     }     cout << ans <<   n ;     return 0;   }   