#include <bits/stdc++.h>   using namespace std;   const int NMax = 110000;   const long long INF = 4294967296LL;   int N, sum[NMax];   char A[NMax];   int S[NMax], L;   unsigned int dp[3][NMax];   int main() {     scanf( %d %s , &N, A);     if (N & 1) {       puts( 0 );       return 0;     }     int cur = 1, cnt = 0;     dp[1][0] = 1;     for (int i = 0; i < N; i++) {       cur = 1 - cur;       int start = 1 - (i & 1), end = min(N / 2, i + 1);       if (A[i] ==  ? )         for (int j = start; j <= end; j += 2)           dp[cur][j] = dp[1 - cur][j + 1] + (j > 0 ? dp[1 - cur][j - 1] : 0);       else {         cnt++;         for (int j = start; j <= end; j += 2)           dp[cur][j] = j > 0 ? dp[1 - cur][j - 1] : 0;       }     }     if (cnt > N / 2) {       puts( 0 );       return 0;     }     cnt = N / 2 - cnt;     while (cnt--) dp[cur][0] *= 25;     printf( %u n , dp[cur][0]);     return 0;   }   