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 Fortran (gfortran v4.8.4) (judge verdict: Wrong Answer)

program name
    use,intrinsic :: iso_fortran_env
    implicit none
    integer(int32):: n,i,c,ans,na
    integer(int32), allocatable:: a(:)
    read*, n
    allocate(a(n))
    do i=1,n
        read*, a(i)
    end do

    call merge_sort(a,1,n)
    na=0
    c=0
    ans=0
    do i=1,n
        if (na == a(i)) then
            c=c+1
        else
            ans=ans+and(c,1)
            c=1
            na=a(i)
        end if
    end do
    print*, ans

    
contains
    recursive subroutine merge_sort(ar, fst, lst)
        integer(4),intent(inout):: ar(:)
        integer(4),intent(in):: fst,lst
        integer(4):: mdl

        if (lst-fst < 2) then
            if (ar(fst) > ar(lst)) call swap(ar(fst),ar(lst))
            return
        end if

        mdl = (fst+lst)/2
        call merge_sort(ar, fst, mdl)
        call merge_sort(ar, mdl+1, lst)
        call merge_(ar, fst, mdl, lst)
    end subroutine

    subroutine merge_(ar, fst, mdl, lst)
        integer(4),intent(inout):: ar(:)
        integer(4),intent(in):: fst, mdl, lst
        integer(4),allocatable:: tmp(:)
        integer(4):: li, ri, ti

        allocate(tmp(lst-fst+1))

        li=fst
        ri=mdl+1   
        ti=1

        do while (li <= mdl .and. ri <= lst)
            if (ar(li) <= ar(ri)) then
                tmp(ti) = ar(li)
                li=li+1
            else
                tmp(ti) = ar(ri)
                ri=ri+1
            end if
            ti=ti+1
        end do

        if (li <= mdl) then
            tmp(ti:) = ar(li:mdl)
        else
            tmp(ti:) = ar(ri:lst)
        end if

        ar(fst:lst) = tmp(:)
        deallocate(tmp)
    end subroutine

    subroutine swap(x,y)
        integer(4),intent(inout):: x,y
        integer(4):: tmp
        tmp = x
        x = y
        y = tmp
    end subroutine
end program name