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 (Clang 3.8.0) (judge verdict: Accepted)

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

#define BUF_SIZE 15

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

int main(void) {
  FILE *fp = stdin;
  char line[BUF_SIZE];
  if(!fgets(line, BUF_SIZE, fp)) return 0;
  int num;
  sscanf(line, "%d", &num);

  int i, j;
  int *arr = malloc(sizeof(int)*num);
  for(i = 0; i < num; i++) {
    if(!fgets(line, BUF_SIZE, fp)) return 0;
    sscanf(line, "%d", &arr[i]);
  }
  qsort(arr, num, sizeof(int), comp);

  int res = 0;
  for(i = 0; i < num;) {
    j = i;
    int cnt = 0;
    while(arr[j] == arr[i]) {
      cnt++;
      i++;
    }
    res += (cnt&1);
  }
  printf("%d\n", res);
  return 0;
}