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 Java (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Object o = run();
        if (o != null)
            System.out.println(o);
    }

    static Object run() {
        try (Scanner sc = new Scanner(System.in)) {
            long result = 0;
            int n = sc.nextInt();
            ArrayList<Integer> a = new ArrayList<>();
            for (int i = 0; i < n; i++) {
                a.add(sc.nextInt());
            }
            Collections.sort(a);
            int latestNum = -1;
            for (int i = a.size() - 1; i >= 0; i--) {
                int Num = a.get(i);
                if (Num != latestNum) {
                    latestNum = Num;
                    result++;
                } else {
                    latestNum = -1;
                    result--;
                }
            }
            return result;
        }
    }
}

class ChenNumberUtil {
    static Collection<Integer> getDivisors(int n) {
        ArrayList<Integer> al = new ArrayList<>();
        for (int i = 1; i * i <= n; i++) {
            if (n % i == 0) {
                al.add(i);
                if (n / i != i)
                    al.add(n / i);
            }
        }
        Collections.sort(al);
        return al;
    }
}

class ChenBitUtil {
    static int popCount(int bit) {
        return Integer.bitCount(bit);
    }

    static boolean isFlag(int bit, int i) {
        return 0 != (bit & (1 << i));
    }

    static int setTrue(int bit, int i) {
        return bit |= (1 << i);
    }

    static int setFalse(int bit, int i) {
        return bit &= ~(1 << i);
    }

    static int setReverse(int bit, int i) {
        return isFlag(bit, i) ? setFalse(bit, i) : setTrue(bit, i);
    }

    static int reverseAll(int bit) {
        return ~bit;
    }
}