program main
    implicit none
    integer:: l, i,j,k
    character(100):: s
    read*, s
    l = len_trim(s)

    do i = 1,l
        if ((mod(i,2) == 0).and. (s(i:i) == 'R'))then
            print*, 'No'
            stop
        else if((mod(i,2) == 1) .and. (s(i:i) == 'L'))then
            print*, 'No'
            stop
        end if
    enddo

    print*, 'Yes'

    
end program