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: Wrong Answer)


#include <stdio.h>
#include <stdlib.h>

int asc(const void *a, const void *b){
    long *A = (long *)a;
    long *B = (long *)b;
    if(*A > *B)
        return 1;
    if(*A < *B)
        return -1;
    return 0;
}

int main(){
    int N, i, cnt=0, tag=0, ans=0;
    long int a[100000];

    scanf("%d", &N);
    for(i=0; i<N; i++){
        scanf("%ld", &a[i]);
    }

    qsort(a, N, sizeof(long int), asc);

    for(i=0; i<N; i++){
        if(a[tag] == a[i]){
            cnt++;
        }
        else{
            if(cnt%2!=0 || cnt==0)
                ans++;
            cnt=0;
            tag = i;
        }
    }

    printf("%d\n", ans);

    return 0;
}