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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <iostream>
#include <string>
#include <sstream>
#include <iomanip>
#include <vector>
#include <map>
#include <set>
#include <algorithm>
#include <numeric>
#include <queue>

using namespace std;
using ll = long long;

void ABC073C()
{
	int N;
	cin >> N;
	set<ll> numbers;
	for (int i = 0; i < N; ++i)
	{
		int x;
		cin >> x;
		auto p = numbers.find(x);
		if (p == numbers.cend())
			numbers.insert(x);
		else
			numbers.erase(p);
	}
	cout << numbers.size() << endl;
}
int main()
{
	ABC073C();
	return 0;
}