func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 2e5;   const int P = 1e9 + 7;   char s[N + 10];   int dp[N + 10][4];   int main() {     int n;     cin >> n >> (s + 1);     dp[0][0] = 1;     for (int i = 1; i <= n; i++) {       if (s[i] !=  ? ) {         memcpy(dp[i], dp[i - 1], sizeof(dp[i]));         (dp[i][s[i] -  a  + 1] += dp[i - 1][s[i] -  a ]) %= P;       } else {         memcpy(dp[i], dp[i - 1], sizeof(dp[i]));         dp[i][0] = 3ll * dp[i][0] % P;         for (int j = 1; j <= 3; j++) {           dp[i][j] = (3ll * dp[i][j] + dp[i - 1][j - 1]) % P;         }       }     }     cout << dp[n][3];   }   