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: Wrong Answer)

var n:longint;
    i:longint;
    a:array[0..200050]of longint;
    num,ans:longint;

procedure qs(l,r:longint);
var i,j,m,t:longint;
begin
  i:=l;
  j:=r;
  m:=a[(l+r)>>1];
  repeat
    while a[i]<m do inc(i);
    while a[j]>m do dec(j);
    if i<=j then
    begin
      t:=a[i];a[i]:=a[j];a[j]:=t;
      inc(i);
      dec(j);
    end;
  until i>j;
  if l<j then qs(l,j);
  if i<r then qs(i,r);
end;
begin
  read(n);
  for i:=1 to n do
  read(a[i]);
  qs(1,n);
  for i:=1 to n do
  if a[i]<>a[i-1] then
  begin
    if num mod 2=1 then inc(ans);
    num:=1;
  end else inc(num);
  writeln(ans);
end.