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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;
import java.math.*;

class Main{       
   public static void main(String[] args){

     Scanner sc = new Scanner(System.in);  
      
     int N = sc.nextInt();
    
     HashMap<Integer,Integer> map = new HashMap<Integer,Integer>();
     
     for(int i = 0;i < N;i++){
         int a = sc.nextInt();
         if(map.containsKey(a)){
             map.put(a,(map.get(a)+1)%2);
         }else{
            map.put(a,1);
         }         
     }
     
     int count = 0;
     for(int key:map.keySet()){
         if(map.get(key) > 0){
             count++;
         }
     }
     
     System.out.println(count);
      
   }
}