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 Java7 (OpenJDK 1.7.0) (judge verdict: Accepted)

import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
import java.util.Set;

/**
 * Created by Xianda Xu on 2018/12/30.
 */
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        Map map = new HashMap<>();
        int N = scanner.nextInt();
        for(int i=0;i<N;i++){
            int key = scanner.nextInt();
            Integer o = (Integer)map.get(key);
            if(o==null){
                map.put(key,1);
            }else{
                map.put(key,o+1);
            }
        }
        int count=0;
        Set<Map.Entry> set = map.entrySet();
        for(Map.Entry entry : set){
            if((int)entry.getValue()%2==1){
                count++;
            }
        }
        System.out.println(count);
    }
}