func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     long long int n, m, b, r;     cin >> n >> m;     b = 3;     r = 1;     while (n > 0) {       if (n % 2 != 0) r = (r * b) % m;       b = (b * b) % m;       n = n / 2;     }     cout << (r - 1 + m) % m;     return 0;   }   