program main
  implicit none
  integer i
  character(3) S 
  read(*, *) S
  !read(*, *) (L(i), i = 1,N)
  if (S == 'AAA') then
    write(*, *) 'No'
  elseif (S == 'BBB') then
    write(*, *) 'No'
  else
    write(*, *) 'Yes'
  endif
end program main
