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 (Clang 3.8.0) (judge verdict: Time Limit Exceeded)

#include <stdio.h>
int main() {
	int n,ai,sum = 0,a[100000];
	a[0] = -1;
	scanf("%d",&n);
	for(int i = 0;i < n;i++) {
// 		printf("%d:\n",i);
// 		for(int k = 0;a[k] != -1;k++) printf("%d\n",a[k]);
		scanf("%d",&ai);
		for(int j = 0;j < 100000;j++) {
			if(a[j] == -1) {
				a[j] = ai;
				if(j != 100000 - 1) a[j+1] = -1;
// 				printf("check\n");
				break;
			}
			if(a[j] == ai) {
				a[j] = 0;
				break;
			}
		}
	}
	for(int i = 0;i < 100000;i++) {
		if(a[i] == -1) break;
		if(a[i] != 0) sum += 1;
	}
// 	printf("result:\n");
// 	for(int i = 0;a[i] != -1;i++) printf("%d\n",a[i]);
	printf("%d\n",sum);
	return 0;
}