func_code_string: #include <bits/stdc++.h>   using namespace std;   int fx[] = {1, -1, 0, 0};   int fy[] = {0, 0, 1, -1};   int main() {     long long n;     cin >> n;     if (n == 1)       cout << 1;     else if (n == 2)       cout << 3;     else {       n += 3;       long long a = 0, b = 1;       for (int i = 2; i <= n; i++) {         long long c = (a + b) % 1000000007;         a = b % 1000000007;         b = c % 1000000007;       }       cout << (b - 2 + 1000000007) % 1000000007 <<   n ;     }   }   