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: Time Limit Exceeded)

#include<stdio.h>

int main(){
  long box[100000],box2[100000]={};
  long a[100000],n,i,cnt=0,cnt2=0,j;
  scanf("%ld",&n);
  for(i=0;i<n;i++)
    scanf("%ld",&a[i]);
  for(i=0;i<n;i++){
    for(j=0;j<cnt2;j++){
      if(a[i]==box[j]&&box2[j]==0){
        cnt++;
        box2[j]=1;
        break;
      }
      else if(a[i]==box[j]&&box2[j]==1){
        cnt--;
        box2[j]=0;
        break;
      }
    }
    if(j==cnt2){
      box[cnt2]=a[i];
      box2[cnt2]=1;
      cnt++;
      cnt2++;
    }
  }
  printf("%ld\n",cnt);
}