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
    }*/

    static void Main(String[] args) {
        int n = Convert.ToInt32(Console.ReadLine());
        string p = Console.ReadLine();
        string numbers = "0123456789";
        string lower = "abcdefghijklmnopqrstuvwxyz";
        string upper = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        string spe = "!@#$%^&*()-+";
        int num = 0;
        int low = 0;
        int up = 0;
        int sp = 0;
        for (int i = 0; i < n; i++){
            if (numbers.Contains(p[i]))
                num = 1;
            if (lower.Contains(p[i]))
                low = 1;
            if (upper.Contains(p[i]))
                up = 1;
            if (spe.Contains(p[i]))
                sp = 1;                        
        }
        int r = num + low + up + sp;
        int answer = 0;
        if (n >= 6){
            if (r == 4)
                answer = 0;
            else 
                answer = 4 - r;
        }
        else{
            answer = Math.Max(6 - n, 4 - r);
        }
        //int answer = minimumNumber(n, password);
        Console.WriteLine(answer);
    }
}