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 Ruby (2.3.3) (judge verdict: Runtime Error)

n = gets.to_i
sum = 1
paper = [gets.to_i]

(n-1).times do
	a_i = gets.to_i

	headIndex = 0
	tailIndex = sum - 1

	loop do
		centerIndex = (headIndex+tailIndex)/2
#== debug
#		p "centerIndex = #{centerIndex}"
#		p "paper = #{paper}"
#		p "sum = #{sum}"
#==
		if paper[centerIndex] == a_i then
			paper.delete_at(centerIndex)
			sum -= 1
			break
		elsif  paper[centerIndex] < a_i then
			if centerIndex == headIndex then
				if paper[centerIndex+1] == a_i then
					paper.delete_at(centerIndex+1)
					sum -= 1
					break
				else
					paper.insert(centerIndex+1, a_i)
					sum += 1
					break
				end
			else
				headIndex = centerIndex
			end
		else
			tailIndex = centerIndex
		end

		if headIndex == tailIndex then
			paper.insert(headIndex, a_i)
			sum += 1
			break
		end
	end
end

p sum