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;
using System.Text;
using System.Threading.Tasks;

namespace Practice
{
    class Program
    {
        static void Main(string[] args)
        {
            string szLine = Console.ReadLine();
            
            long n = long.Parse(szLine);
            var dic = new Dictionary<long, int>();// key 数字、value 総数

            for (long i = 0;i<n;++i)
            {
                szLine = Console.ReadLine();
                long a = long.Parse(szLine);
                if( dic.ContainsKey(a))
                {
                    dic[a]++;
                }
                else
                {
                    dic.Add(a, 1);
                }
            }
            int total = 0;
            var keys = dic.Keys;
            foreach(long a in keys)
            {
                if( dic[a] % 2 != 0)
                {
                    total += 1;
                }
            }

            Console.WriteLine(total);
        }
    }
}