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 = "!@#$%^&*()-+";
        boolean isNumber = false;
        boolean isLower = false;
        boolean isUpper = false;
        boolean isSpecial = false;
        for (int i = 0; i < password.length(); i++) {
            for (int j = 0; j < numbers.length(); j++) {
                if (password.charAt(i) == numbers.charAt(j)) {
                    isNumber = true;
                }
            }
            for (int j = 0; j < lower_case.length(); j++) {
                if (password.charAt(i) == lower_case.charAt(j)) {
                    isLower = true;
                }
            }
            for (int j = 0; j < upper_case.length(); j++) {
                if (password.charAt(i) == upper_case.charAt(j)) {
                    isUpper = true;
                }
            }
            for (int j = 0; j < special_characters.length(); j++) {
                if (password.charAt(i) == special_characters.charAt(j)) {
                    isNumber = true;
                }
            }
        }
        int num = 0;
        if (isNumber == false) {
            num++;
        }
        if (isLower == false) {
            num++;
        }
        if (isUpper == false) {
            num++;
        }
        if (isSpecial == false) {
            num++;
        }
        return 6 - n + num
    }

    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();
    }
}