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>
#include<stdlib.h>
struct node {
	int num;
	struct node* next;
};
void add(struct node *root,int num) {
	struct node* new = malloc(sizeof(struct node));
	new->num = num;
	new->next = root->next;
	root->next = new;
}
int delete(struct node* root, int num) {
	struct node* p = root;
	struct node* q = root->next;

	while (q!=NULL)
	{
		if (q->num == num) {
			p->next = q->next;
			free(q);
			return 1;
		}
		p = p->next;
		q = q->next;
	}
	return 0;
}
int main() {
	int n;
	int i = 0, j = 0, k;
	scanf("%d",&n);

	struct node* root = malloc(sizeof(struct node));
	root->next = NULL;
	root->num = -1;

	int* b=malloc(sizeof(int *)*n);
	for ( i = 0; i < n; i++){
		scanf("%d", &b[i]);
		if (delete(root, b[i]) == 0)
			add(root, b[i]);
	}

	int count = 0;
	struct node* p = root->next;
	while (p!=NULL){
		p = p->next;
		count++;
	}
	printf("%d", count);
	return 0;
}