#include <bits/stdc++.h>

using namespace std;
string numbers = "0123456789";
string lower_case = "abcdefghijklmnopqrstuvwxyz";
string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
string special_characters = "!@#$%^&*()-+";
int minimumNumber(int n, string password) {
    int count = 0;
    int count2 = 0;
    //length 6
    if(n < 6){
        count2 = 6 - n;
    }
    //one digit
    if(password.find_first_of(numbers) == string::npos){
        count +=1;
    }
    //one lowercase
    if(password.find_first_of(lower_case) == string::npos){
        count +=1;
    }
    //one uppercase
    if(password.find_first_of(upper_case) == string::npos){
        count +=1;
    }
    //one special
    if(password.find_first_of(special_characters) == string::npos){
        count +=1;
    }
    return max(count, count2);
    // 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;
}