#include <bits/stdc++.h>   using namespace std;   unsigned int dp[100100];   char s[100100];   int main() {     unsigned int n;     cin >> n;     if (n & 1) {       return !printf( 0 );     }     scanf( %s , s + 1);     int m = n / 2;     dp[0] = 1;     for (int i = 1; i <= n; i++) {       if (s[i] ==  ? ) {         for (int j = i / 2; j >= max(1, i - m); j--) dp[j] += dp[j - 1];       }     }     for (int i = 1; i <= n; i++) {       if (s[i] ==  ? ) continue;       m--;     }     for (int i = 1; i <= m; i++) dp[n / 2] *= 25;     cout << dp[n / 2] <<   n ;     return 0;   }   