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: Time Limit Exceeded)

using System;
using System.Collections.Generic;

class Program
{
	static void Main(string[] args)
	{
        int n;
        List<int> list = new List<int>();
        n = int.Parse(Console.ReadLine());
        int sum = 0;



        for (int i = 0;i < n;i++){

            int a = int.Parse(Console.ReadLine());
            bool addList = true;

            for (int j = 0; j < list.Count;j++){

                if (list[j] == a)
                {
                    list.RemoveAt(j);
                    sum -= 1;
                    addList = false;
                    break;
                }
            }

            if(addList)
            {
                list.Add(a);
                sum += 1;
            };

        }

        Console.WriteLine(sum);

	}
}