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
        bool digit = false;
        bool lowercase = false;
        bool uppercase = false;
        bool specialCharacter = false;
        int counter = 0;

        do
        {
            if (!digit)
            {
                if (Char.IsDigit(password[counter]))
                {
                    digit = true;
                    goto label;
                }
            }
            if(!lowercase)
            {
                if (Char.IsLower(password[counter]))
                {
                    lowercase = true;
                    goto label;
                }
            }
            if(!uppercase)
            {
                if (Char.IsUpper(password[counter]))
                {
                    uppercase = true;
                    goto label;
                }
            }
            if(!specialCharacter)
            {
                if (IsSpecialCharacter(password[counter]))
                    specialCharacter = true;
            }

            label:

            if (digit && lowercase && uppercase && specialCharacter)
                break;

            counter++;

        } while (counter < n);

        counter = 0;

        if (!digit) counter++;
        if (!lowercase) counter++;
        if (!uppercase) counter++;
        if (!specialCharacter) counter++;

        if ((n + counter) < 6)
            counter = 6 - n;

        return counter;
    }
    
    static bool IsSpecialCharacter(char ch)
    {
        char[] specialArray = { '!', '@', '#', '$', '%', '^', '&', '*', '(', ')', '-', '+' };

        for (int i = 0; i < specialArray.Length; i++)
        {
            if (ch == specialArray[i])
                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);
    }
}