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>

long int *Marge(long int *A,long int N){
	
	if(N==1){
		long int *C=malloc(sizeof(long int));
		C=A;
		return C;
	}

	if (N>1){
		long int N1=N/2;
		long int N2=N-N1;
		long int *A1=malloc(N1*sizeof(long int));
		long int *A2=malloc(N2*sizeof(long int));
		long int i=0;
		for (i=0;i<N1;i++){
			A1[i]=A[i];
		}
		for (i=N1;i<N;i++){
			A2[i-N1]=A[i];
		}
		long int *B1=Marge(A1,N1);
		long int *B2=Marge(A2,N2);

		long int *C=malloc(N*sizeof(long int));

		long int k=0;
		long int l=0;
		long int m=0;

		while(1){
			if (k>=N1){
				for (m;m<N;m++){
					C[m]=B2[l];
					l++;
				}
				break;
			}
			if (l>=N2){
				for (m;m<N;m++){
					C[m]=B1[k];
					k++;
				}
				break;
			}		
			else{
				if (B1[k]<=B2[l]){
					C[m]=B1[k];
					m++;
					k++;
				}
				if (B1[k]>B2[l]){
					C[m]=B2[l];
					m++;
					l++;
				}
			}
		}
		return C;
	}

}



int main(){
	long int N;
	scanf("%ld",&N);

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

	long int *B=malloc(N*sizeof(long int));
	B=Marge(A,N);

	long int j=0;
	long int sum;
	long int ans=0;
	while(j<N){
		sum=0;
		long int b=B[j];
		while (j<N && B[j]==b) {
			sum++;
			j++;
		}
		ans+=sum%2;
	}	
	printf("%ld\n",ans);
}