#include <bits/stdc++.h>

using namespace std;

int contains(string s, string cs){
    for (char& c:cs){
        if (string::npos != s.find(c)) return 1;
    }
    return 0;
}

int minimumNumber(int n, string password) {
    string numbers = "0123456789";
    string lower_case = "abcdefghijklmnopqrstuvwxyz";
    string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    string special_characters = "!@#$%^&*()-+";
    int a = contains(password, numbers) + contains(password, lower_case) +contains(password, upper_case)                        +contains(password, special_characters);
    return max(6-n, 4-a);
}

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