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

public class Solution {
    final static int minLength = 6;
    static String numbers = "0123456789";
    static String lower_case = "abcdefghijklmnopqrstuvwxyz";
    static String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    static String special_characters = "!@#$%^&*()-+";
    
    static boolean checkLength(String password){
        if(password.length() < minLength){
            return false;
        }
        return true;
    }
    static boolean checkCharacters(String characters, String password){
        char[] charArray = characters.toCharArray();
        char[] passArray = password.toCharArray();
        boolean ok = false;
        for(int i = 0; i<charArray.length; i++)
            for(int j = 0; j<passArray.length; j++){
                if(passArray[j] == charArray[i]) {
                    ok=true;
                    return true;
                }   
        }
        return false;
    }
    static int minimumNumber(int n, String password) {
        int answer = 0;
        if(!checkCharacters(numbers, password)){
            answer += 1;
        }
        if(!checkCharacters(lower_case, password)){
            answer += 1;
        }
        if(!checkCharacters(upper_case, password)){
            answer += 1;
        }
        if(!checkCharacters(special_characters, password)){
            answer += 1;
        }
        if(!checkLength(password)){
            int delta = minLength - password.length();
            if(answer<delta){
                answer = delta;
            }
        }
        return answer;
    }

    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();
    }
}