using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace foryuki
{
    class Program
    {
        static void Main(string[] args)
        {
            int N = int.Parse(Console.ReadLine());
            List<int> s = ConvertStringArrayToIntList(Console.ReadLine().Split());

            for (int i = 0; i < s.Count; i++)
            {
                var Q = from word in s
                        where word == s[i]
                        select word;
                if (Q.Count() > 1)
                {
                    s.RemoveAll(x => x == s[i]);
                    i -= 1;
                }
            }
            Console.WriteLine(s.Count);
        }


        //-------------------------------------------------------------

        static int[] ConvertStringArrayToIntArray(string[] str)
        {
            int[] b = Array.ConvertAll<string, int>(str, delegate(string value)
                {
                    return int.Parse(value);
                });
            return b;
        }

        static List<int> ConvertStringArrayToIntList(string[] str)
        {
            var list = new List<int>();
            foreach (var c in str)
            {
                list.Add(int.Parse(c));
            }
            return list;
        }
    }
}