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 (GCC 5.4.1) (judge verdict: Accepted)

#include <stdio.h>
#include <stdlib.h>

void msort();
void merge();

void mergesort(long deta[], int size){
	long temp[size];
	msort(deta, temp, 0, size-1);
}

void msort(long date[], long temp[], int left, int right){
	int mid;

	if(left >= right) return;
	else{
		mid = (left + right)/2;

		msort(date, temp, 	 left, mid  );
		msort(date, temp, mid + 1, right);

		merge(date, temp, left, mid, right);		
	}
}

void merge(long date[], long temp[], int left, int mid, int right){
	int i, j, tmp_pos;

	i = left;
	j = mid + 1;

	tmp_pos = left;

	while(i<=mid && j<=right){
		if(date[i] > date[j]){
			temp[tmp_pos] = date[j];
			j++;
			tmp_pos++;
		}else{
			temp[tmp_pos] = date[i];
			i++;
			tmp_pos++;
		}
	}

	while(i<=mid){
		temp[tmp_pos] = date[i];
		i++;
		tmp_pos++;
	}

	while(j<=right){
		temp[tmp_pos] = date[j];
		j++;
		tmp_pos++;
	}

	for(i=left; i<=right; i++){
		date[i] = temp[i];
	}
}

int main(){
	long A[100000];
	int i,N,now,result,ct;

	scanf("%d", &N);

	for(i=0; i<N; i++){
		scanf("%ld", &A[i]);
	}

	mergesort(A,N);

	i = 0;
	result = 0;

	while(i<N){
		now = A[i];

		ct = 1;
		i++;
		while(A[i] == now){
			ct++;
			i++;
		}
		if(ct%2 == 1) result++;

	}

	printf("%d\n", result);

  return 0;
}