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 <bits/stdc++.h>
using namespace std;
using ll = long long;
using ldb = long double;
using pa = pair < ll, ll >;
using vec = vector < ll >;
#define pb push_back
#define F  first
#define S  second
#define f(i,x,n) for(ll i=x;i<n;i++) 
#define all(c) c.begin(),c.end()
#define edl "\n"
#define str string
#define fast() ios_base::sync_with_stdio(false);cin.tie(NULL)
const int MOD = 1e9 + 7, N = 1e5 + 10;
const ll LINF = LLONG_MAX;
int main() {
    fast();
 
    ll n;
    cin >> n;
    set<ll>s;
    f(i,0,n)
    {
        ll x;
        cin >>x;
        if(s.find(x)!=s.end())
        {
            s.erase(x);
        } 
        else
            s.insert(x);
    }   

    cout<<s.size();
    cerr << "Time taken: " << int((clock() * 1000.) / CLOCKS_PER_SEC) << "ms\n";
    return 0;
}