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 = "!@#$%^&*()-+";
        int count = 0;
      if (!contains(password, numbers)) count++;
      if (!contains(password, lower_case)) count++;
      if (!contains(password, upper_case)) count++;
      if (!contains(password, special_characters)) count++;
      int delta = Math.max(0, 6 - count - password.length());
      count += delta;
      return count;
    }
  
    private static boolean contains(String s, String oneOf) {
      for (char c: oneOf.toCharArray()) {
        if (s.indexOf(c) != -1) {
          return true;
        }
      }
      return false;
    }

    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();
    }
}