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

class Program
{
    static void Main(string[] args)
    {
        int N = int.Parse(Console.ReadLine());
        string[] A = Console.ReadLine().Split(' ');

        List<string> aList = new List<string>();
        aList.AddRange(A);
        aList.Sort();

        int i = 0;
        do
        {
            if (aList.Count(x => x == aList[i]) > 1)
            {
                aList.RemoveAll(x => x == aList[i]);
                if (aList.Count < i + 1) { break; }
            }
            else { i++; }
        } while (aList.Count != i + 1);
        
        Console.WriteLine(aList.Count());
    }
}