#include <bits/stdc++.h>
using namespace std;
const int N = 100004;
int n;
unsigned f[N];
char s[N];
int main() {
  int i, j;
  scanf("%d%s", &n, s + 1);
  if (n % 2) {
    printf("0\n");
    return 0;
  }
  f[1] = 1;
  for (i = 2; i <= n + 1; i++) f[i] = 0;
  for (i = 1; i <= n; i++)
    if (s[i] == '?')
      for (j = i % 2; j <= i; j += 2) f[j + 1] = f[j] * 25 + f[j + 2];
    else
      for (j = i % 2; j <= i; j += 2) f[j + 1] = f[j];
  printf("%u\n", f[1]);
  return 0;
}
