using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static void Main(String[] args)
    {
        var N = int.Parse(Console.ReadLine());
        var input = Console.ReadLine().Split(' ')
                                      .Select(x => int.Parse(x))
                                      .ToList();
        var removeList = new List<int>();
        var search = 0;
        for (int i = 0; i < N; i++)
        {
            search = input[i];
            if (removeList.Contains(search)) continue;
            for (int j=i+1; j<N; j++)
            {
                if (search == input[j]) { removeList.Add(search); break; }
            }
        }
        input = input.Except(removeList).ToList();
        var novelty = input.Count();
        Console.WriteLine(novelty);
    }
}