program main
  implicit none
  integer*4::DA
  integer*4,allocatable::a(:)
  integer*4::b(0:2),asum
  integer::i
  read *,DA
  allocate(a(0:DA))
  read *,a(0:DA)

  asum = SUM(a(1:DA))
  b(0) = a(0)
  b(1) = SUM(a(1:DA:2))
  b(2) = asum -b(1)

  if(b(2).ne.0) then
     print '("2",/,i0,1x,i0,1x,i0)', b
  else if(b(1).ne.0) then
     print '("1",/,i0,1x,i0)', b(0:1)
  else
     print '("0",/i0)', b(0)
  end if
end program main