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 C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;


int main () {
    vector<long long int> vec;
    vector<long long int> vec2;
    int n, z;
    int ptr = 0;
    int ptr2 = 0;
    cin >> n;

    for (int i = 0 ; i < n; i++ ) {
        cin >> z;
        vec.push_back(z);

    }

    sort(vec.begin(), vec.end());

    ptr2 = ptr;
    while (ptr < n) {
        while (ptr2+ptr < n && vec[ptr] == vec[ptr+ptr2]) {
            ptr2++;
        }
        if (ptr2 % 2 != 0) vec2.push_back(vec[ptr]);
        ptr += ptr2;
        ptr2 = 0;

    }

    cout << vec2.size() << endl;
    return 0;
}