#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string password) {
    // Return the minimum number of characters to make the password strong
    string numbers = "0123456789";
    string lower_case = "abcdefghijklmnopqrstuvwxyz";
    string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    string special_characters = "!@#$%^&*()-+";
    
    int addNumber = 1;
    int addLowerCase = 1;
    int addUpperCase = 1;
    int addSpecial = 1;

    for (int i=0; i<n; ++i) {
        char a = password[i];
        if (a >= numbers[0] && a <= numbers[9]) {
            addNumber = 0;
        } else if (a >= lower_case[0] && a <= lower_case[25]) {
            addLowerCase = 0;
        } else if (a >= upper_case[0] && a <= upper_case[25]) {
            addUpperCase = 0;
        } else {
            for (int j=0; j<special_characters.size(); ++j) {
                if (a == special_characters[j]) {
                    addSpecial = 0;
                    break;
                }
            }
        }
        
        if (addNumber == 0 && addLowerCase == 0 && addUpperCase == 0 && addSpecial == 0) {
            break;
        }
    }
    
    return max(addNumber + addLowerCase + addUpperCase + addSpecial, 6-n);
}

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