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 Scala (2.11.7) (judge verdict: Runtime Error)

object Main extends App {
  val s = new java.util.Scanner(System.in)
  val n = s.next().toInt
  val ns = (1 to n).map(_ => s.next().toLong).sorted.toList
  println(group(ns).filter(_._2%2 == 1).length)

  
  def group(l: List[Long]): List[(Long, Long)] = {
    def g(l: List[(Long, Long)]): List[(Long, Long)] = l match {
      case x::y::ll => if (x==y) {g((x._1, x._2+y._2)::ll)} else {x::g(y::l)} 
      case List(x)  => List(x)
      case List()   => List()
    }
    g(l.map((_, 1L)))
  }
}