#include <iostream>
#include <string>

using namespace std;

int minimumNumber(int n, string password) {
    // Return the minimum number of characters to make the password strong
    bool isLower=false, isUpper=false, isNumber=false, isSpecial=false;
    string numbers, lower_case, upper_case, special_characters;
    numbers = "0123456789";
    lower_case = "abcdefghijklmnopqrstuvwxyz";
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    special_characters = "!@#$%^&*()-+";
    isLower=!(string::npos==password.find_first_of(lower_case));
    isUpper=!(string::npos==password.find_first_of(upper_case));
    isNumber=!(string::npos==password.find_first_of(numbers));
    isSpecial=!(string::npos==password.find_first_of(special_characters));
    int missing_spec_let=4-isLower-isUpper-isNumber-isSpecial;
    int missing_num_let=6-n;
    //cout<<missing_spec_let<<' '<<missing_num_let<<endl;
    if (missing_num_let<=0)
        missing_num_let=0;
    return missing_spec_let>missing_num_let?missing_spec_let:missing_num_let;
}

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