s = gets.split("")
len = s.length
j = 0
0.step(len-1, 2){|i|
if s[i] == "L"
    j = 1
    print "No"
    break
end

if s[i+1] == "R"
    j = 1
    print "No"
    break
end
}
if j == 0
    print "Yes"
end