program b
implicit none

integer :: I, L
character(100) :: S

read(*,*) S
S = trim(S)
L = len(S)

do I = 1, L, 2
 if (S(I:I)=="L") then
 write(*,'(a2)') "No"
 stop
 end if
end do

do I = 2, L, 2
 if (S(I:I)=="R") then
 write(*,'(a2)') "No"
 stop
 end if
end do

write(*,'(a3)') "Yes"

end program