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

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

int main(){

  int n;
  scanf("%d",&n);

  int a[100000];
  for(int i = 0; i < n; ++i){
    scanf("%d",&a[i]);
  }
  a[n+1] = 0;

  qsort(a,n,sizeof(int),sort);

  int ans = 0;
  int tmp = 0;
  if(n == 1){
    ans = 1;
  }else{
  for(int i = 0; i < n; ++i){
    if(a[i] == a[i+1]){
      ++ tmp;
    }
    if(a[i] != a[i+1]){
      if(tmp % 2 == 0){
        ans ++;
      }
      tmp = 0;
    }
  }
  }

  printf("%d",ans);

  return 0;

}