func_code_string: #include <bits/stdc++.h>   using namespace std;   template <typename Arg1>   void __f(const char* name, Arg1&& arg1) {     cerr << name <<   :   << arg1 <<   n ;   }   template <typename Arg1, typename... Args>   void __f(const char* names, Arg1&& arg1, Args&&... args) {     const char* comma = strchr(names + 1,  , );     cout.write(names, comma - names) <<   :   << arg1 <<   |  ;     __f(comma + 1, args...);   }   long long pows(long long b, long long e) {     if (e == 0)       return 1;     else if (e % 2 == 0) {       long long a = pow(b, e / 2);       return a * a;     } else {       long long a = pow(b, e / 2);       return b * a * a;     }   }   long long powm(long long x, long long y, long long m) {     x = x % m;     long long res = 1;     while (y) {       if (y & 1) res = res * x;       res %= m;       y = y >> 1;       x = x * x;       x %= m;     }     return res;   }   long long modInverse(long long a, long long m = 1000000007) {     if (m == 1) return 0;     long long m0 = m, y = 0, x = 1;     while (a > 1) {       long long q = a / m, t = m;       m = a % m, a = t;       t = y;       y = x - q * y;       x = t;     }     if (x < 0) x += m0;     return x;   }   int main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     long long n, m, i, j, k, x, y, z, e, f, p, q, g, l, r, w, h,         count1 = 0, prod = 1, a, b, c, d, index, x1, x2, diff, ans = 0, sum = 0,         sum1 = 0, sum2 = 0, flag = 0, flag1 = 0, flag2 = 0;     string s, s1, s2;     cin >> n;     if (n == 1) {       cout <<  1 ;       return 0;     } else {       ans = 1;       k = 3;       for (i = 2; i <= n; i++) {         ans += k * 4;         k += 3;       }       cout << ans;     }   }   