#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string password) {
    bool digit = false;
    bool lower = false;
    bool upper = false;
    bool special = false;
    for (char c : password) {
        if (c >= 'a' && c <= 'z') {
            lower = true;
        } else if (c >= 'A' && c <= 'Z') {
            upper = true;
        } else if (c >= '0' && c <= '9') {
            digit = true;
        } else {
            special = true;
        }
    }
    return max(!digit + !lower + !upper + !special, 6 - n);
}

int main() {
    int n;
    cin >> n;
    string password;
    cin >> password;
    int answer = minimumNumber(n, password);
    cout << answer << endl;
    return 0;
}