#include <bits/stdc++.h>
using namespace std;

int main() {
	int n;
    cin >> n;

    int unknownCnt = 0;

    for (int i = 0; i < n; i++) {
        char c;
        cin >> c;

        if (c == '_') {
            unknownCnt++;
        }
    }

    int possible = 26 - (n - unknownCnt);

    int res = 1;

    for(int i = 0; i < unknownCnt; i++) {
        res *= possible;
        possible--;
    }

    cout << res << endl;
}