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) {
       String numbers = "0123456789";
String lower_case = "abcdefghijklmnopqrstuvwxyz";
String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
String special_characters = "!@#$%^&*()-+";
            int i,x=0,h=0,c=0,l=0,y=0,s=0;
        for(i=0;i<password.length();i++)
        {
            if(numbers.indexOf(password.charAt(i))>=0)
            {
                x=1;
            }
            if(lower_case.indexOf(password.charAt(i))>=0)
            {
                l=1;
            }
            if(upper_case.indexOf(password.charAt(i))>=0)
            {
                h=1;
            }
            if(special_characters.indexOf(password.charAt(i))>=0)
            {
                s=1;
            }
            
        }
        if(x==0)
        {
            c++;
        }
        if(l==0)
        {
            c++;
        }
        if(h==0)
        {
            c++;
        }
        if(s==0)
        {
            c++;
        }
        if(c+password.length()<6)
        {
            return 6-password.length();
        }
        else
        {
            return c;
        }
        
           
        // Return the minimum number of characters to make the password strong
    }

    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();
    }
}