#! ruby
# yukicoder My Practice
# author: Leonardone @ NEETSDKASU
############################################################
def gs() gets.chomp end
def gi() gets.to_i end
def gf() gets.to_f end
def gss() gs.split end
def gis() gss.map(&:to_i) end
def gfs() gss.map(&:to_f) end
def nmapf(n,f) n.times.map{ __send__ f } end
def ngs(n) nmapf n,:gs end
def ngi(n) nmapf n,:gi end
def ngss(n) nmapf n,:gss end
def ngis(n) nmapf n,:gis end
def arr2d(h,w,v=0) h.times.map{[v] * w} end
def for2p(hr,wr,&pr) hr.each{|i|wr.each{|j| yield(i,j)}} end
def nsum(n) n * (n + 1) / 2 end
def vcount(d,r=Hash.new(0)) d.inject(r){|r,e| r[e]+=1;r} end
############################################################

t = 0

loop {
    s = STDIN.gets
    break if s[0] == "M"
    if s.size > 2
        STDOUT.puts "F"
    else
        d = s.to_i
        case t
        when 0
            if d == 0
                puts "R"
            else
                puts "F"
                t = 1
            end
        when 1
            puts "R"
            t = 2
        when 2
            if d == 0
                puts "L"
            else
                puts "F"
            end
            t = 0
        end
    end
    STDOUT.flush
}