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>
#define rep(i, n) for(int i=0; i<(n); ++i)
#define rep1(i,n) for(int i=1; i<=(n); ++i)
#define repi(i,a,b) for(int i=a; i<=(b); ++i)
#define rrep(i,n) for(int i=(n-1); i>=0; --i)
#define ALL(obj) (obj).begin(), (obj).end()
#define RALL(obj) (obj).rbegin(), (obj).rend()
#define pb push_back
#define mp make_pair
#define to_s to_string
#define sz(v) (int)v.size()
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() )
#define pr(x) cout<<(x)<<'\n'
#define debug(x) cout << #x << ": " << (x) << '\n'
#define yes "Yes"
#define no "No"
using ll = long long;
using namespace std;
typedef pair<int,int> P;
struct aaa{aaa(){ cin.tie(0); ios::sync_with_stdio(0); cout<<fixed<<setprecision(20);};}aaaaaaa;
int MOD = 1e9 + 7;
int gcd(int a,int b){return b?gcd(b,a%b):a;}
int lcm(int a,int b){return (a*b)/gcd(a,b);}
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};

int N,a;
int main(){
    cin >> N;
    set<int> st;
    rep(i,N){
        cin >> a;
        if(st.find(a) == st.end()) st.insert(a);
        else st.erase(a);
    }
    pr(sz(st));
}