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

    static int minimumNumber(int n, string password) {
        
        var numbers = "0123456789";
        var lower_case = "abcdefghijklmnopqrstuvwxyz";
        var upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        var special_characters = "!@#$%^&*()-+";
        
        bool un=false,ul=false,uu=false,us=false;
        
        foreach(var c in password)
        {
            if (numbers.IndexOf(c)>=0) un=true;
            if (lower_case.IndexOf(c)>=0) ul=true;
            if (upper_case.IndexOf(c)>=0) uu=true;
            if (special_characters.IndexOf(c)>=0) us=true;
        }

        var min = Math.Max(6-n,0);
        var needed = (un?0:1) + (ul?0:1) + (uu?0:1) + (us?0:1);
        return Math.Max(min, needed);
        
        // Return the minimum number of characters to make the password strong
    }

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