import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

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

    static int minimumNumber(int n, String password) {
        boolean hasNumber = false;
        boolean hasLowerCase = false;
        boolean hasUpperCase = false;
        boolean hasSpecial = false;
        for (char c : password.toCharArray()) {
            String s = "" + c;
            if (numbers.contains(s)) hasNumber = true;
            if (lower_case.contains(s)) hasLowerCase = true;
            if (upper_case.contains(s)) hasUpperCase = true;
            if (special_characters.contains(s)) hasSpecial = true;
        }
        int out = 0;
        if (!hasNumber) out++;
        if (!hasLowerCase) out++;
        if (!hasUpperCase) out++;
        if (!hasSpecial) out++;
        return Math.max(6-n, out);
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        String password = in.next();
        int answer = minimumNumber(n, password);
        System.out.println(answer);
        in.close();
    }
}