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>
//#include <string.h>
//#include <stdbool.h>
//#include <limits.h>
//#include <math.h>

//昇順
int acs(const void *a, const void *b)
{
  return *(int *)a - *(int *)b;
}

int main() {
  int n;
  scanf("%d", &n);
  int a[n];
  for (int i=0; i<n; i++)
    scanf("%d", a+i);
  qsort(a, n, sizeof(int), acs);
  int ans = 0, p = 0, cnt = 0;
  for (int i=0; i<n; i++) {
    if (p == a[i] && cnt == 0) {
      ans++;
      cnt++;
    } else if (p == a[i] && cnt == 1) {
      ans--;
      cnt--;
    } else {
      ans++;
      cnt = 1;
      p = a[i];
    }
  }
  printf("%d\n", ans);
  return 0;
}