using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
class Solution {

    static int minimumNumber(int n, string password) {
        // Return the minimum number of characters to make the password strong
        var numbers = "0123456789";
var lower_case = "abcdefghijklmnopqrstuvwxyz";
var upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
var special_characters = "!@#$%^&*()-+";
        bool b1 = false, b2 = false, b3 = false, b4= false;
        for(int i=0;i<password.Length; i++)
        {
            if(numbers.Contains(password[i])) b1 = true;
                        if(lower_case.Contains(password[i])) b2 = true;

                        if(upper_case.Contains(password[i])) b3 = true;

                        if(special_characters.Contains(password[i])) b4 = true;

        }
        int add = 0;
        if(b1 == false) add +=1;
        if(b2==false) add +=1;
        if(b3==false) add +=1;
        if(b4==false) add +=1;
       
        if(password.Length +add >6)
        return  add;
        else
            return add+(6-add-password.Length);
            
            
    }

    static void Main(String[] args) {
        int n = Convert.ToInt32(Console.ReadLine());
        string password = Console.ReadLine();
        int answer = minimumNumber(n, password);
        Console.WriteLine(answer);
    }
}