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 V1503;
 var
  a:array[0..100001] of longint;
  i,n,s,p:longint;
 procedure haha(l,r:longint);
  var
   o,p,m,t:longint;
  begin
   o:=l;
   p:=r;
   m:=a[(l+r) div 2];
   repeat
    while a[o]<m do inc(o);
    while a[p]>m do dec(p);
    if o<=p then
     begin
      t:=a[o];
      a[o]:=a[p];
      a[p]:=t;
      inc(o);
      dec(p);
     end;
   until o>p;
   if o<r then haha(o,r);
   if l<p then haha(l,p);
  end;
 begin
  readln(n);
  for i:=1 to n do
   readln(a[i]);
  haha(1,n);
  a[0]:=-1008208820;
  a[n+1]:=1008208820;
  s:=0;
  p:=0;
  for i:=1 to n+1 do
   if a[i]<>a[i-1] then
    begin
     if p mod 2=1 then inc(s);
     p:=1;
    end
                   else inc(p);
  writeln(s);
 end.