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: Wrong Answer)

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef string str;
using P = pair<int, int>;
const ll inf =1e9;
const ll linf = 1e18;

struct edge{
    int to;
    int cost;
};
using graph = vector<vector<edge>>;

int main(){
    int n; cin >> n;
    vector<int> a(n);
    for(int i=0; i<n; i++){
        int tmp; cin >> tmp;
        a[i] = tmp;
    }
    sort(a.begin(), a.end());
    int ans = 0;
    int cur_ans = 1;
    int tmp = a[0];
    for(int i=1; i<n; i++){
        if(a[i] == tmp){
            cur_ans += 1;
        }else{
            if(cur_ans %2 == 1){
                ans += 1;
            }
            cur_ans = 1;
            tmp = a[i];
        }
    }
    cout << ans << endl;
    return 0;
}