      PROGRAM piyo
      IMPLICIT NONE
      logical ::flag = .false.
      character(3) :: s
      integer :: i
      
      read*,s
      
      
      do i = 1,2
        if( s(i:i)/=s(i+1:i+1) ) flag = .true.
      end do
      
      if( flag )then
        print*,'Yes'
      else
        print*,'No'
      end if
      
      
      
      
      END PROGRAM