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

class TEST
{
    static void Main()
    {
        new Sol();//.Solve();
    }
}


public class A
{
    public int val;
    public int b = 1;
}

class Sol
{
    
    public Sol()
    {
        int N = Convert.ToInt32(Console.ReadLine());
        
        List<A> listA = new List<A>();
        A tempa = new A();

        tempa.val = Convert.ToInt32(Console.ReadLine());
        listA.Add(tempa);

        for (int i = 0; i < N-1; i++) {
                      
            int a = Convert.ToInt32(Console.ReadLine());

            A c = listA.Find(x => x.val == a);
            if (c != null)
            {
                c.b = (c.b + 1) % 2 ;
            }
            else { 
                A d = new A();
                d.val = a;
                listA.Add(d);
            }
        }

        int cnt = 0;
        for (int i = 0; i < listA.Count; i++) {
            if (listA[i].b == 1) {
                cnt++;
            }
        }

        Console.WriteLine(cnt);
    }
}