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 Pascal (FPC 2.6.2) (judge verdict: Accepted)

program  ec12;
var 
	n,m,i,j,ans,tot:longint;
	a:array[1..100001] of longint;
procedure qsrt(l,r:longint);
var 
	i,j,v,s:longint;
begin
	i:=l; j:=r; v:=a[(l+r) div 2];
	repeat
	while a[i]<v do inc(i);
	while a[j]>v do dec(j);
	if i<=j then 
	begin 
		s:=a[i];
		a[i]:=a[j];
		a[j]:=s;
		inc(i);
		dec(j);
	end;
	until i>=j;
	if l<j then qsrt(l,j);
	if i<r then qsrt(i,r);
end;
begin 
	readln(n);
	for i:=1 to n do
	readln(a[i]);
	qsrt(1,n);
	tot:=1;
	ans:=0;
	for i:=2 to n do 
	begin 
		if a[i]=a[i-1] then 
		inc(tot)
		else
		begin 
			if tot mod 2=1 then 
			inc(ans);
			tot:=1;
		end;
	end;
	if tot mod 2=1 then 
	inc(ans);
	writeln(ans);
end.