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>
int main(){
	int N,i,j,k,n,ans=0;
	scanf("%d",&N);
	int a[100000]={0};
	k=0;
	for(i=0;i<N;i++){
		int m;
		scanf("%d",&m);
		for(j=0;j<k;j++){
			if(m==a[j]){
				break;
			}
		}
		if(m==a[j]){
			if(k==1){
				a[0]=0;
			}
			else if(m==k-1){
				a[m]=0;
			}
			else{
				for(n=j;n<k-1;n++){
					a[n]=a[n+1];
				}
				a[k-1]=0;
			}
			k--;
			ans--;
		}
		else{
			a[k++]=m;
			ans++;
		}
	}
	printf("%d\n",ans);
	return 0;
}