Problem:
Score : 300 points

Problem Statement

You are playing the following game with Joisino.

Initially, you have a blank sheet of paper.

Joisino announces a number. If that number is written on the sheet, erase the number from the sheet; if not, write the number on the sheet. This process is repeated N times.

Then, you are asked a question: How many numbers are written on the sheet now?

The numbers announced by Joisino are given as A_1, ... ,A_N in the order she announces them. How many numbers will be written on the sheet at the end of the game?

Constraints

1≤N≤100000

1≤A_i≤1000000000(=10^9)

All input values are integers.

Input

Input is given from Standard Input in the following format:

N
A_1
:
A_N

Output

Print how many numbers will be written on the sheet at the end of the game.

Sample Input 1

3
6
2
6

Sample Output 1

1

The game proceeds as follows:

6 is not written on the sheet, so write 6.

2 is not written on the sheet, so write 2.

6 is written on the sheet, so erase 6.

Thus, the sheet contains only 2 in the end. The answer is 1.

Sample Input 2

4
2
5
5
2

Sample Output 2

0

It is possible that no number is written on the sheet in the end.

Sample Input 3

6
12
22
16
22
18
12

Sample Output 3

2

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

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

namespace ABC073_C_Write_and_Erase
{
	internal class Program
	{
		public static void Main(string[] args)
		{
			int n = int.Parse(Console.ReadLine());
			List<int> aList = new List<int>();
			for (int i = 0; i < n; i++)
				aList.Add(int.Parse(Console.ReadLine()));
			
			aList.Sort();
			
			//解説スライドを見て書いたコード
			int count = 1;
			int result = 0;
			for (int i = 0; i < n - 1; i++)
			{
				if (aList[i] == aList[i + 1])
				{
					count++;
				}
				else
				{
					if (count % 2 == 1) result++;
					count = 1;
				}
				
				if (i == n - 2 && count % 2 == 1) result++;
			}
			
			Console.WriteLine(result);

			//自分で書いたコード
			/*int count = aList.Count;
			for (int i = 0; i < n;)
			{
				int countNumbers = aList.Count(x => x == aList[i]);
				if (countNumbers % 2 == 1)
					count -= countNumbers - 1;
				else
					count -= countNumbers;

				i += countNumbers;
			}

			Console.WriteLine(count);*/
		}
	}
}