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 s="0123456789";
        boolean number=false;
        char toSearch=s.charAt(0);
        for(int i=0;i<s.length();i++)
        {
            toSearch=s.charAt(i);
            if(password.indexOf(toSearch)!=-1)
            {
                number=true;
                break;
            }
        }
        String lower_case = "abcdefghijklmnopqrstuvwxyz";
        boolean lower=false;
        toSearch=lower_case.charAt(0);
        for(int i=0;i<lower_case.length();i++)
        {
            toSearch=lower_case.charAt(i);
            if(password.indexOf(toSearch)!=-1)
            {
                lower=true;
                break;
            }
        }
        String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        boolean upper=false;
        
         for(int i=0;i<upper_case.length();i++)
        {
            toSearch=upper_case.charAt(i);
            if(password.indexOf(toSearch)!=-1)
            {
                upper=true;
                break;
            }
        }
        
        boolean special=false;
        String special_characters = "!@#$%^&*()-+";
          for(int i=0;i<special_characters.length();i++)
        {
            toSearch=special_characters.charAt(i);
            if(password.indexOf(toSearch)!=-1)
            {
                special=true;
                break;
            }
        }
       int req_digits=0;
        if(!number){req_digits++;
                    n++;}
        if(!lower){req_digits++;
                   n++;}
        if(!upper){req_digits++;
                   n++;}
        if(!special){req_digits++;
                     n++;}
       int ans=6-n;
        if(ans<=0)
            return req_digits;
        
            return ans+req_digits;
        
    }

    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();
    }
}