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: Time Limit Exceeded)

#include <stdio.h>

#define N_MAX 100000
#define A_MAX 1000000000

int main(void)
{
	int n, i, j, flag, count = 0;
	unsigned long a;
	unsigned long memo[N_MAX];

	for(i=0;i<n;i++) {
		memo[i] = 0;
	}

	scanf("%d%*c", &n);

	for(i=0;i<n;i++) {
		scanf("%lu%*c", &a);
		flag = 0;
		for(j=0;j<i;j++) {
			if(memo[j] == a) {
				memo[j] = 0;
				flag = 1;
				break;
			}
		}
		if(flag) continue;
		memo[i] = a;
	}

	for(i=0;i<n;i++) {
		if(memo[i]) count++;
	}

	printf("%d\n", count);
	
	return 0;
}