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>

int compare(const void *a,const void *b);

int main(void){

    int N,i,k,count=0,F=0,A[100000];
    scanf("%d",&N);
    if(1>N||100000<N){
        printf("Wrong number.\n");
        return 0;
    }
    for(i=0;i<N;i++){
        scanf("%d",&A[i]);
        if(A[i]<1||A[i]>1000000000){
            printf("Wrong number.\n");
            return 0;
        }
    }
    qsort(A,N,sizeof(int),compare);
/*
    printf("*************\n");
    for(i=0;i<N;i++){
        printf("%d\n",A[i]);
    }
    printf("*************\n");
*/
    k = A[0];
    for(i=1;i<N;i++){
        if(k!=A[i]){
            k = A[i];
            if(F%2==0){
                count++;
            }
            F = 0;
        }else if(k==A[i]){
            F++;
        }
/*
        printf("A[%d] = %d, F = %d, count = %d\n",i,A[i],F,count);
*/
    }
    if(F==0||F%2==0)count++;
    printf("%d\n",count);

return 0;
}

int compare(const void *a,const void *b){
    return *(int*)a - *(int*)b;
}