func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n;     cin >> n;     long long int x = 0;     for (int i = 2; i <= n; ++i) {       if (i & 1)         x = (x * 3 - 3) % 1000000007;       else         x = (x * 3 + 3) % 1000000007;     }     cout << x << endl;     return 0;   }   