import java.util.Scanner;

public class Strong_Password {

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

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        String password = sc.next();
        int weakness = 4;
        for (char c : numbers.toCharArray()) {
            if (password.indexOf(c) != -1) {
                weakness--;
                break;
            }
        }
        for (char c : lower_case.toCharArray()) {
            if (password.indexOf(c) != -1) {
                weakness--;
                break;
            }
        }
        for (char c : upper_case.toCharArray()) {
            if (password.indexOf(c) != -1) {
                weakness--;
                break;
            }
        }
        for (char c : special_characters.toCharArray()) {
            if (password.indexOf(c) != -1) {
                weakness--;
                break;
            }
        }
        if (n + weakness < 6) {
            System.out.println(6 - n);
        } else {
            System.out.println(weakness);
        }
    }

}