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
            int countn=0;
            int countl=0;
            int countu=0;
            int counts=0;
            int answer=4;
            String numbers = "0123456789";
            String lower_case = "abcdefghijklmnopqrstuvwxyz";
            String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
            String special_characters = "!@#$%^&*()-+";
            for(int i=0;i<password.length();i++)
            {
                for(int j=0;j<numbers.length();j++)
                    if(password.charAt(i)==numbers.charAt(j))
                        countn++;
                for(int j=0;j<lower_case.length();j++)
                    if(password.charAt(i)==lower_case.charAt(j))
                        countl++;
                for(int j=0;j<upper_case.length();j++)
                    if(password.charAt(i)==upper_case.charAt(j))
                        countu++;
                for(int j=0;j<special_characters.length();j++)
                    if(password.charAt(i)==special_characters.charAt(j))
                        counts++;
            }
            if(countn>0)
                answer--;
            if(countl>0)
                answer--;
            if(countu>0)
                answer--;
            if(counts>0)
                answer--;
            if(answer+password.length()>=6)
                return answer;
            else
            {
                return 6-password.length();
            }
                
            
    }

    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();
    }
}