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>
#include "stdlib.h"

int search(int *datas, int n, int number);

int main() {
    int count;
    int *datas, number, inCount, index;
    scanf("%d", &count);
    datas = (int *) malloc(count * sizeof(int));
    inCount = 0;
    for (int j = 0; j < count; ++j) {
        datas[j] = 0;
    }
    for (int i = 0; i < count; ++i) {
        scanf("%d", &number);
        if ((index = search(datas, count, number)) != -1) {
            inCount--;
            datas[index] = 0;
        } else {
            datas[inCount] = number;
            inCount++;
        }
    }
    printf("%d", inCount);
    return 0;
}

int search(int *datas, int n, int number) {
    for (int i = 0; i < n; ++i) {
        if (datas[i] == number) {
            return i;
        }
    }
    return -1;
}