using System;
using System.Linq;

namespace StudyApp
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            var a = Console.ReadLine().Trim().Split(' ').Select(data => int.Parse(data));
            var b = a.Distinct();

            var result = a.OrderBy(data => data)
                .Where(data => a.Where(value => value.Equals(data)).Count() == 1);

            Console.WriteLine(result.Count());
        }
    }
}