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 (1.14.1) (judge verdict: Accepted)

package main

import (
        "fmt"
)

func solution(n int, a []int) int {
        memo := make(map[int]int)
        for i := range a {
                if n, ok := memo[a[i]]; ok {
                        if n > 1 {
                                memo[a[i]]--
                        } else {
                                delete(memo, a[i])
                        }
                } else {
                        memo[a[i]]++
                }
        }
        return len(memo)
}

func main() {
        var n int
        fmt.Scan(&n)
        a := make([]int, n)
        for i := range a {
                fmt.Scan(&a[i])
        }
        fmt.Println(solution(n, a))
}