using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;

class Solution {

    private static Regex r_numbers = new Regex ("0|1|2|3|4|5|6|7|8|9");
    private static Regex r_letters_low = new Regex ("a|b|c|d|e|f|g|h|i|j|k|l|m|n|o|p|q|r|s|t|u|v|w|x|y|z");    
    private static Regex r_letters_high = new Regex ("A|B|C|D|E|F|G|H|I|J|K|L|M|N|O|P|Q|R|S|T|U|V|W|X|Y|Z");
    private static Regex r_symbols;
    
    
    static int minimumNumber(int n, string password) {  
        int missing = 0;
        
        if(r_numbers.IsMatch(password) == false) {
            missing++;
        }
        if(r_letters_low.IsMatch(password) == false) {
            missing++;
        }
        if(r_letters_high.IsMatch(password) == false) {
            missing++;
        }
        if(r_symbols.IsMatch(password) == false) {
            missing++;
        }
        
        return Math.Max(missing, 6-n);
    }

    static void Main(String[] args) {
        
        string sym = "";
        
        foreach( char c in "!@#$%^&*()-+") {
            sym += Regex.Escape("" + c) + "|"; 
        }
        sym = sym.Remove(sym.Length - 1);
        
        r_symbols = new Regex (sym);
        
        int n = Convert.ToInt32(Console.ReadLine());
        string password = Console.ReadLine();
        int answer = minimumNumber(n, password);
        Console.WriteLine(answer);
    }
}