program main
  implicit none
  integer*8::DA,DB
  integer*8,allocatable::a(:)
  integer::i
  read *,DA
  allocate(a(0:DA))
  read *,a

  do i=DA, 3, -1
     a(i-2) = a(i-2) + a(i)
  end do

  do i=2, 0, -1
     if(a(i).ne.0) exit
  end do
  if(a(2).ne.0) then
     print '(i0)', 2
     print '(i0,1x,i0,1x,i0)', a(0:2)
  else if(a(1).ne.0) then
     print '(i0)', 1
     print '(i0,1x,i0)', a(0:1)
  else
     print '(i0)', 0
     print '(i0)', a(0)
  end if
end program main