func_code_string: #include <bits/stdc++.h>   using namespace std;   long long M = 1000000007;   long long bigMod(long long n, long long power, long long mod = M) {     if (power == 0) return 1;     if (power == 1)       return n % mod;     else if (power % 2 == 0) {       long long v = bigMod(n, power / 2, mod);       return ((v % mod) * (v % mod)) % mod;     } else {       long long v = bigMod(n, power - 1, mod) % mod;       return ((v % mod) * (n % mod)) % mod;     }   }   int main() {     long long n;     scanf( %lld , &n);     long long number = bigMod(2, n);     cout << ((number * (number + 1)) / 2) % M << endl;     return 0;   }   