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++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <bits/stdc++.h>
using namespace std;

int main(){
  long long int N, ans = 0, pre, count = 1;
  cin >> N;
  vector<long long int> A(N);
  for (long long int i = 0; i < N; i++){
    cin >> A[i];
  }
  
  sort(A.begin(), A.end());
  pre = A[0];
  
  for (int i = 1; i < N; i++){
    if (pre == A[i]){
      count += 1;
    }else{
      if (count % 2 == 1){
        ans += 1;
      }
      pre = A[i];
      count = 1;
    }
  }
  
  if (count > 1 && count % 2 == 1){
    ans += 1;
  }
  cout << ans << endl;
}