program main
  implicit none
  integer :: i
  character(4) :: s, res
  read (*, *) s
  res = "Good"
  do i = 1, 3
    if (s(i:i) == s(i + 1:i + 1)) then
      res = "Bad"
    end if
  end do

  write (*, "(a)") trim(res)
end program main
