func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     long long a = 1, b = 1;     int n;     cin >> n;     for (int i = 1; i <= n; i++) {       a = a * 27 % 1000000007;       b = b * 7 % 1000000007;     }     cout << (a + 1000000007 - b) % 1000000007;     return 0;   }   