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: Wrong Answer)

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

int main() {
  int N, *A, sum = 0, i, j, a, k, b = 0;

  scanf("%d", &N);
  A = (int*)malloc(sizeof(int) * N);
  for (i = 0; i < N; i++) {
    A[i] = 0;
  }

  for (i = 0; i < N; i++, b = 0) {
    scanf("%d", &a);
    for (j = 0; j < sum; j++) {
      if (A[j] == a) {
        A[j] = 0;
        for (k = sum - 1; k > j; k--) {
          A[k - 1] = A[k];
        }
        sum--;
        b = 1;
        break;
      }
    }
    if (b == 0) {
      A[sum] = a;
      sum++;
    }
  }
  printf("%d\n", sum);
  return 0;
}