import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class StrongPassword {
    
    static final String numbers = "0123456789";
    static final String lower_case = "abcdefghijklmnopqrstuvwxyz";
    static final String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    static final String special_characters = "!@#$%^&*()-+";

    static int minimumNumber(int n, String password) {
        boolean hasN = contains(password, numbers);
        boolean hasL = contains(password, lower_case);
        boolean hasU = contains(password, upper_case);
        boolean hasS = contains(password, special_characters);
        int toAdd = (hasN ?  0 : 1)
                + (hasL ?  0 : 1)
                + (hasU ?  0 : 1)
                + (hasS ?  0 : 1); 
        
        return Math.max(toAdd, 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();
    }

    private static boolean contains(String password, String what) {
        for (Character c : password.toCharArray()) {
            for (char w : what.toCharArray()) {
                if (w == c) {
                    return true;
                }
            }
        }
        return false;
    }
    
}