using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
class Solution {
    
    static string numbers = "0123456789";
    static string lower_case = "abcdefghijklmnopqrstuvwxyz";
    static string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    static string special_characters = "!@#$%^&*()-+";

    static int minimumNumber(int n, string password) {
        // Return the minimum number of characters to make the password strong
        
        bool hasNumber = false;
        bool hasLower = false;
        bool hasUpper = false;
        bool hasSign = false;
        int reqC = 6 - n;
        int req = 0;
        
        for(int x=0;x<n;x++) {
            if(hasNumber == false) {
                for(int i = 0;i<numbers.Length;i++) {
                    if(password[x] == numbers[i]) {
                        hasNumber = true;
                        break;
                    }
                }
            }
            if(hasLower == false) {
                for(int i = 0;i<lower_case.Length;i++) {
                    if(password[x] == lower_case[i]) {
                        hasLower = true;
                        break;
                    }
                }
            }
            if(hasUpper == false) {
                for(int i = 0;i<upper_case.Length;i++) {
                    if(password[x] == upper_case[i]) {
                        hasUpper = true;
                        break;
                    }
                }
            }
            if(hasSign == false) {
                for(int i = 0;i<special_characters.Length;i++) {
                    if(password[x] == special_characters[i]) {
                        hasSign = true;
                        break;
                    }
                }
            }
        }
        
        if(hasNumber == false)
                req++;
            if(hasLower == false)
                req++;
            if(hasUpper == false)
                req++;
            if(hasSign == false)
                req++;
        
        return Math.Max(reqC, req);
    }

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