implicit none
character(100) :: s
integer :: l

read*,s
l = trim_len( s )

do i = 1,l
  if( mod(i,2)==1 )then
    if( s(i:i)=='L' ) goto 100
  else
    if( s(i:i)=='R' ) goto 100
  end if
end do

print*,'Yes'
stop

100 continue
print*,'No'
end