//package com.adobe.common;

import java.util.*;

public class Solution {
	
	static int minimumNumber(int n, String password) {
		/*
		numbers = "0123456789"
		lower_case = "abcdefghijklmnopqrstuvwxyz"
		upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
		special_characters = "!@#$%^&*()-+"
		*/
		HashSet<Character> numbers = new HashSet<Character>();
		for (int i = 0; i < 10; i++) {
			numbers.add((char) (i + 48));
		}
		
		HashSet<Character> lower_case = new HashSet<Character>();
		for (int i = 0; i < 26; i++) {
			lower_case.add((char) (i + 97));
		}
		HashSet<Character> upper_case = new HashSet<Character>();
		for (int i = 0; i < 26; i++) {
			upper_case.add((char) (i + 65));
		}
		HashSet<Character> special = new HashSet<Character>();
		special.add('!');
		special.add('@');
		special.add('#');
		special.add('$');
		special.add('%');
		special.add('^');
		special.add('&');
		special.add('*');
		special.add('(');
		special.add(')');
		special.add('-');
		special.add('+');
		
		boolean isNumber = false;
		boolean isLowerCase = false;
		boolean isUpperCase = false;
		boolean isSpecialChar = false;
		int count = 0;
		
		for (char c : password.toCharArray()) {
			if (numbers.contains(c)) {
				isNumber = true;
			} else if (lower_case.contains(c)) {
				isLowerCase = true;
			} else if (upper_case.contains(c)) {
				isUpperCase = true;
			} else if (special.contains(c)) {
				isSpecialChar = true;
			}
		}
		if (!isNumber) {
			count++;
		}
		if (!isLowerCase) {
			count++;
		}
		if (!isUpperCase) {
			count++;
		}
		if (!isSpecialChar) {
			count++;
		}
		if (password.length() + count < 6) {
			count += (6 - (password.length() + 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();
	}
}