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)

var
 a:array[1..100001] of longint;
 n,m,k,i,j:longint;
procedure swap(var a, b: longint);
var
  temp: longint;
begin
  temp := a;
  a := b;
  b := temp;
end;

procedure quicksort(l, r: longint);
var
  border, i: longint;
begin
  if l < r then begin
    swap(a[random(r - l + 1) + l], a[r]);
    border := l;
    for i := l to r - 1 do
      if (a[i] < a[r]) or ((a[i] = a[r]) and (random(2) = 1)) then begin
        swap(a[border], a[i]);
        inc(border);
      end;
    swap(a[border], a[r]);
    quicksort(l, border - 1);
    quicksort(border + 1, r);
  end;
end;

begin
 readln(n);
 for i:=1 to n do
  readln(a[i]);
 quicksort(1,n);
 i:=1;
 k:=0;
 while (i<=n) do
  begin
   j:=i;
   while (j<=n) and (a[j]=a[j+1]) do
    inc(j);
    inc(k,(j-i+1) mod 2);
    i:=j+1;
  end;
 writeln(k);
end.