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 numbers = "0123456789";
        String lower_case = "abcdefghijklmnopqrstuvwxyz";
        String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        String special_characters = "!@#$%^&*()-+";

		Set<Character> passwordSet = new HashSet<Character>();
		for(int i=0; i<n; i++){
			passwordSet.add(password.charAt(i));
		}
		int count = 0;
		boolean hasNumbers = false;
		for(int i=0; i<numbers.length(); i++){
			if(passwordSet.contains(numbers.charAt(i))){
				hasNumbers = true;
				break;
			}				
		}
		boolean hasLowerCase = false;
		for(int i=0; i<lower_case.length(); i++){
			if(passwordSet.contains(lower_case.charAt(i))){
				hasLowerCase = true;
				break;
			}				
		}
		boolean hasUpperCase = false;
		for(int i=0; i<upper_case.length(); i++){
			if(passwordSet.contains(upper_case.charAt(i))){
				hasUpperCase = true;
				break;
			}				
		}
		boolean hasSpecialChar = false;
		for(int i=0; i<special_characters.length(); i++){
			if(passwordSet.contains(special_characters.charAt(i))){
				hasSpecialChar = true;
				break;
			}				
		}
		if(!hasNumbers)
			count++;
		if(!hasUpperCase)
			count++;
		if(!hasLowerCase)
			count++;
		if(!hasSpecialChar)
			count++;
		if( n + count < 6)
			count += (6 - (n+count));
		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();
    }
}