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

public class Solution {

    static 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 valid = containsEle(password, numbers) + containsEle(password, lower_case) + containsEle(password, upper_case) + containsEle(password, special_characters);
        if (valid + n < 6)
        		valid = 6 - n;
        return valid;
    }
    
    private static int containsEle(String password, String refer) {

        for (char cha: refer.toCharArray()) {
            if(password.indexOf(cha) >= 0) return 0;
        }
        return 1;
    }

    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();
    }
}