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.Linq;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        var numx = ReadInts();
        var n = numx[0];
        var singled = Enumerable.Repeat(1, n).Select(_ => ReadInts()).Select(p => p[0]).ToLookup(p => p).Select(p => p.Count()).Count(p => p % 2 == 1);

        Console.WriteLine(singled);
    }

    static int Caloc(int v, int w, int n)
    {
        n++;
        var vp = GetParents(v-1, n);
        var wp = GetParents(w-1, n);
        var pp = vp.Zip(wp, (p, q) => new Point(p, q)).TakeWhile(p => p.X == p.Y).Select(p => p.X).ToArray();
        return GetNode(pp, n) + 1;
    }


    static int GetNode(IEnumerable<int> source, int n)
    {
            return source.Aggregate(0, (a, p) => a * n + p);
    }
    static IEnumerable<int> GetParents(int v, int n)
    {
        return GetParentsItr(v, n).Reverse();
    }
    static IEnumerable<int> GetParentsItr(int v, int n)
    {
        while (v > 0)
        {
            yield return v % n;
            v /= n;
        }
    }

    #region Utils
    static int[] ReadInts()
    {
        return Console.ReadLine().Split().Select(int.Parse).ToArray();
    }
    #endregion
}

struct Point
{
    public Point(int x, int y)
    {
        X = x;
        Y = y;
    }

    public int X { get; }
    public int Y { get; }
}