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;

class Program
{
    static string InputPattern = "InputX";

    static List<string> GetInputList()
    {
        var WillReturn = new List<string>();

        if (InputPattern == "Input1") {
            WillReturn.Add("3");
            WillReturn.Add("6");
            WillReturn.Add("2");
            WillReturn.Add("6");
            //1
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("4");
            WillReturn.Add("2");
            WillReturn.Add("5");
            WillReturn.Add("5");
            WillReturn.Add("2");
            //0
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("6");
            WillReturn.Add("12");
            WillReturn.Add("22");
            WillReturn.Add("16");
            WillReturn.Add("22");
            WillReturn.Add("18");
            WillReturn.Add("12");
            //2
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    static void Main()
    {
        List<string> InputList = GetInputList();
        int[] AArr = InputList.Skip(1).Select(X => int.Parse(X)).ToArray();

        var wkSet = new HashSet<int>();
        foreach (int EachInt in AArr) {
            if (wkSet.Contains(EachInt)) {
                wkSet.Remove(EachInt);
            }
            else wkSet.Add(EachInt);
        }
        Console.WriteLine(wkSet.Count);
    }
}