program station_and_bus
  implicit none
  character(3) :: s
  integer :: n = 0, i
  read(*,*) s
  do i = 1, 3
    n = n+ichar(s(i:i))-65
  end do
  if (n == 0 .or. n == 3) then
    write(*,'(a)') "No"
  else
    write(*,'(a)') "Yes"
  end if
end program station_and_bus