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

public class Main{
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		HashMap<Integer, Integer> mp = new HashMap<Integer, Integer>();
		Set<Integer> set = new HashSet<Integer>();
		for (int i = 0; i < n; i++) {
			int m = scan.nextInt();
			if(set.contains(m)){
				if(mp.containsKey(m)){
					int value=mp.get(m);
					mp.put(m, value+1);
				}else{
					mp.put(m, 1);//不在广场
				}
			}
			set.add(m);

		}
		int count=0;
		for (Entry<Integer, Integer> entry : mp.entrySet()) {
            Integer key = entry.getKey();
            Integer value = entry.getValue();
            if(value%2==1){
            	count++;
            }
          
        }
		System.out.println(set.size()-count);
	}
}