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

namespace yukicoderTest
{
    class Program
    {
        static void Main(string[] args)
        {
            string input = Console.ReadLine();
            string findlist = Console.ReadLine();
            string[] list = findlist.Split(' ');
            int[] num = new int[list.Length];
            int Newcnt = int.Parse(input);
            for (int i=0;i<num.Length;i++)
            {
                num[i] = int.Parse(list[i]);
            }
            for(int i=0;i<num.Length;i+=2)
            {
                for(int j=i+1;j<num.Length;j++)
                {
                    if(num[i]==num[j])
                    {
                        Newcnt-=2;
                        break;
                    }
                }
            }
            
            Console.WriteLine(Newcnt);
        }

    }
}