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 Go (1.6) (judge verdict: Accepted)

package main
 
import (
	"bufio"
	"os"
	"strconv"
	"fmt"
)
  
var sc = bufio.NewScanner(os.Stdin)

func ReadStr() string {
	sc.Scan()
	return sc.Text()
}

func ReadInt() int {
	i, e := strconv.Atoi(ReadStr())
	if e != nil {
		panic(e)
	}
	return i
}

func main() {
	N := ReadInt()
    mp := map[int]bool{}
  	for i := 0; i < N; i++{
      A := ReadInt()
        if _, ok := mp[A]; ok {
          			delete(mp, A)
        } else {
          	mp[A] = true
        }
    }
  	fmt.Println(len(mp))
}