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
        string numbers = "0123456789";
        string lower_case = "abcdefghijklmnopqrstuvwxyz";
        string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        string special_characters = "!@#$%^&*()-+";

        bool nu = false;
        bool lo = false;
        bool up = false;
        bool sp = false;
        int cnt = 0;
        
        for(int i = 0; i < numbers.Length; i++){
            nu = password.Contains(numbers[i]);
            if(nu) break;
        }
        for(int i = 0; i < lower_case.Length; i++){
            lo = password.Contains(lower_case[i]);
            if(lo) break;
        }
        for(int i = 0; i < upper_case.Length; i++){
            up = password.Contains(upper_case[i]);
            if(up) break;
        }
        for(int i = 0; i < special_characters.Length; i++){
            sp = password.Contains(special_characters[i]);
            if(sp) break;
        }
        if(nu == false) cnt++;
        if(lo == false) cnt++;
        if(up == false) cnt++;
        if(sp == false) cnt++;
        if(6 - n < cnt){
            return cnt;
        }else{
            return 6 - n;
        }
    }

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