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;

class Program
{
    static void Main()
    {
        int n = int.Parse(Console.ReadLine());
        List<int> list = new List<int>();
        for (int i = 0; i < n; i++)
            list.Add(int.Parse(Console.ReadLine()));
        list.Sort();
        if (n == 1)
        {
            Console.WriteLine(1);
        }
        else
        {
            int ans = 0;
            int tmp = list[0];
            bool even = false;
            for (int i = 1; i < n; i++)
            {
                if (i == n - 1)
                {
                    if (tmp == list[i])
                    {
                        if (even) ans++;
                    }
                    else if (even) ans++;
                    else ans += 2;
                }
                else
                {
                    if (tmp == list[i])
                    {
                        even = !even;
                    }
                    else
                    {
                        if (even) even = false;
                        else ans++;
                        tmp = list[i];
                    }

                }
            }
            Console.WriteLine(ans);
        }
    }
}