program kadai
implicit none
character(len=100)  ::  S
integer  ::  i,size,flag,gu

read(*,*) S

size=len_trim(S)
flag=0

do i=1,size
    gu=mod(i,2)
    if (gu==0) then
        if (S(i:i)=="R") then
            flag=1
            exit
        end if
    else if (gu==1) then
    if (S(i:i)=="L") then
            flag=1
            exit
        end if
    end if
end do

if (flag==1) then
    write(*,*) "No"
else
    write(*,*) "Yes"
end if
stop
contains

end program kadai