#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string password) {
    vector<bool> characters(4, false);
    string numbers = "0123456789";
    string lower_case = "abcdefghijklmnopqrstuvwxyz";
    string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    string special_characters = "!@#$%^&*()-+";
    for(int i = 0; i < n; i++) {
        char currChar = password[i];
        if(numbers.find(currChar) != string::npos) {
            characters[0] = true;
        }
        else if(lower_case.find(currChar) != string::npos) {
            characters[1] = true;
        }
        else if(upper_case.find(currChar) != string::npos) {
            characters[2] = true;
        }
        else if(special_characters.find(currChar) != string::npos) {
            characters[3] = true;
        }
    }
    int result = n;
    for(int i = 0; i < 4; i++) {
        if(!characters[i]) {
            result++;
        } 
    }
    if(result < 6) {
        result = 6;
    }
    return result - n;
}

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