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) {
            
       boolean num=false;
        boolean low=false;
        boolean high=false;
        boolean special=false;
    String     numbers = "0123456789";
String lower_case = "abcdefghijklmnopqrstuvwxyz";
String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
String special_characters = "!@#$%^&*()-+";
     
        int count=0;
        for(int i=0;i<n;i++){
        
            for(int j=0;j<lower_case.length();j++){
                if(password.charAt(i)==lower_case.charAt(j))
                    low=true;
            }
            
            for(int j=0;j<upper_case.length();j++){
                if(password.charAt(i)==upper_case.charAt(j))
                    high=true;
            }
            
            for(int j=0;j<special_characters.length();j++){
                if(password.charAt(i)==special_characters.charAt(j))
                    special=true;
            }
            
            for(int j=0;j<numbers.length();j++){
                if(password.charAt(i)==numbers.charAt(j))
                    num=true;
            }
        }       
            if(!num)
                count++;
            if(!low)
                count++;
            if(!high)
                count++;
            if(!special)
                count++;
            
            if(count+password.length()<6)
                return (6-password.length());
            else 
                return count;
    }

    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();
    }
}