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

public class Solution {

    static int minimumNumber(int n, String password) {
        
        boolean containsDigit = false;
        boolean lC = false;
        boolean uC = false;
        boolean specialC = false;
        
        int a = 0;
        
        if(password.matches(".*\\d+.*"))
            containsDigit = true;
        else
            a++;
        
        if(password.matches(".*[a-z]+.*"))
            lC=true;
        else
            a++;
        
        if(password.matches(".*[A-Z]+.*"))
            uC=true;
        else
            a++;
        
         Pattern p = Pattern.compile("[^A-Za-z0-9]");
     Matcher m = p.matcher(password);
        if( m.find())
            specialC = true;
        else
            a++;
        
        if(n+a <6)
            return 6-n;
        else
            return a;
    }

    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();
    }
}