#include <iostream>
#include <vector>
#include <string>
#include <algorithm>

using namespace std;

int main()
{
    int chars = 26;
    int unknowns = 0;

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

        if (c == '_')
        {
            unknowns++;
        }
        else
        {
            chars--;
        }
    }

    long int ans = 1;
    for (int i = chars; unknowns > 0; chars--, unknowns--)
    {
        ans *= chars;
    }

    cout << ans;
}