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

int minimumNumber(int n, string password) {
    string numbers = "0123456789";
    string lower_case = "abcdefghijklmnopqrstuvwxyz";
    string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    string special_characters = "!@#$%^&*()-+";
    int nums = 0;
    int lows = 0;
    int ups = 0;
    int specs = 0;
    for(int i = 0; i < n; i++){
        if(numbers.find(password.at(i)) != string::npos){
            nums = 1;
        } else if(lower_case.find(password.at(i)) != string::npos){
            lows = 1;
        } else if(upper_case.find(password.at(i)) != string::npos){
            ups = 1;
        } else if(special_characters.find(password.at(i)) != string::npos){
            specs = 1;
        }
    }
    if(n >= 6){
        return 4 - nums - lows - ups - specs;
    } else {
        return max(6-n,4-nums-lows-ups-specs);
    }
    // Return the minimum number of characters to make the password strong
}

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