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

public class P0182 {
    public static void Main() {
        var n = int.Parse(Console.ReadLine().Trim());
        var dict = new Dictionary<int, int>();
        foreach(int a in Console.ReadLine().Trim().Split(' ').Select(int.Parse)) {
            dict[a] = dict.GetValueOrDefault(a) + 1;
        }
        Console.WriteLine(dict.AsEnumerable().Where(pair => pair.Value == 1).Count());
    }
}