character(100)S
logical Check
read*,S
check=.true.
do i=1,len_trim(S)
  if(mod(i,2)==1)then
    if(S(i:i)=="L")check=.false.
  else
    if(S(i:i)=="R")check=.false.
  endif
end do
if(check)then
  print"(A)","Yes"
else
  print"(A)","No"
endif
end