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

    static int minimumNumber(int n, string password) {
        string numbers = "0123456789";
        string lower_case = "abcdefghijklmnopqrstuvwxyz";
        string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        string special_characters = "!@#$%^&*()-+";
        
        int types = 0;
        
        if (ContainsAny(password, numbers))
            types++;
        if (ContainsAny(password, lower_case))
            types++;
        if (ContainsAny(password, upper_case))
            types++;
        if (ContainsAny(password, special_characters))
            types++;
        
        //Console.Error.WriteLine((6 - n) + " " + (4 - types));
        
        return Math.Max(Math.Max(6 - n, 0), 4 - types);
    }
    
    static bool ContainsAny(string a, string b)
    {
        foreach (char c in b)
        {
            if (a.IndexOf(c) > -1)
            {
                return true;
            }
        }
        return false;
    }

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