import java.util.Scanner;

import static java.lang.Math.max;

public class Main {
    static String numbers = "0123456789";
    static String lower_case = "abcdefghijklmnopqrstuvwxyz";
    static String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    static String special_characters = "!@#$%^&*()-+";

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        scanner.nextInt();
        String password = scanner.next();
        int result = 0;
        if(!containsAny(password, numbers)) result ++;
        if(!containsAny(password, lower_case)) result ++;
        if(!containsAny(password, upper_case)) result ++;
        if(!containsAny(password, special_characters)) result ++;



        System.out.println(max(result, 6 - password.length()));
    }

    private static boolean containsAny(String password, String set) {
        for(int i=0;i<set.length();i++) {
            if(password.contains(""+set.charAt(i)))
                return true;
        }
        return false;
    }
}