#! 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
############################################################

=begin

最大でも20x20なんで
うまくやればTLEなんて起こらないはずなのに

壁伝いだと以下に気をつけるべき

ループに捕まると抜け出せない
##########
#.........
#..####..#
#.v#..#..#
#..####..#
#........#
##########

行き止まりも恐い
##########
#.#.......
#.#.######
#.#......#
#.#.######
#......v.#
##########

下手すると上下左右に単機ループがあるかもしれない
##########
#.........
#...#....#
#.#.v.#..#
#........#
#...#....#
#........#
##########

=end


UNKNOWN_CELL = 0
WALL_CELL = 1
SPACE_CELL = 2

f = arr2d(60, 60)
x = 30
y = 30
dx = 1
dy = 0
f[y][x] = SPACE_CELL

def rot(dx, dy) [-dy, dx] end
def revrot(dx, dy) [dy, -dx] end
def rcell(f, x, y, dx, dy)
    nx, ny = rot(dx, dy)
    f[y + ny][x + nx]
end
def lcell(f, x, y, dx, dy)
    nx, ny = revrot(dx, dy)
    f[y + ny][x + nx]
end

def checkwall(f)
    loop {
        flg = 0
        for2p(9..50,9..50) {|i,j|
            next if f[i][j] != SPACE_CELL
            c = 0
            c += 1 if f[i - 1][j] == WALL_CELL
            c += 1 if f[i + 1][j] == WALL_CELL
            c += 1 if f[i][j - 1] == WALL_CELL
            c += 1 if f[i][j + 1] == WALL_CELL
            if c >= 3
                f[i][j] = WALL_CELL
                flg = 1
            end
        }
        break if flg == 0
    }
    f
end


t = 0

loop {
    s = STDIN.gets
    break if s[0] == "M"
    if s.size > 2
        STDOUT.puts "F"
    else
        d = s.to_i
        if f[y + dy][x + dx] == UNKNOWN_CELL
            (1..d).each do |i|
                f[y + dy * i][x + dx * i] = SPACE_CELL
            end
            f[y + dy * d.succ][x + dx * d.succ] = WALL_CELL
            f = checkwall(f)
        end
        nxt = "X"
        case t
        when 0
            if d == 0
                if rcell(f, x, y, dx, dy) == UNKNOWN_CELL
                    nxt = "R"
                else
                    nxt = "L"
                end
            else
                nxt = "F"
                t = 1
            end
        when 1
            t = 2
            if rcell(f, x, y, dx, dy) == UNKNOWN_CELL
                nxt = "R"
            elsif lcell(f, x, y, dx, dy) == UNKNOWN_CELL
                nxt = "L"
            elsif d > 0
                nxt = "F"
                t = 0
            elsif rcell(f, x, y, dx, dy) == SPACE_CELL
                nxt = "R"
                t = 0
            elsif lcell(f, x, y, dx, dy) == SPACE_CELL
                nxt = "L"
                t = 0
            else
                nxt = "B"
                t = 3
            end
        when 2
            if d == 0
                nxt = "L"
            else
                nxt = "F"
            end
            t = 0
        when 3
            if rcell(f, x, y, dx, dy) == UNKNOWN_CELL
                nxt = "R"
                t = 0
            elsif lcell(f, x, y, dx, dy) == UNKNOWN_CELL
                nxt = "L"
                t = 0
            elsif f[y - dy][x - dx] == WALL_CELL
                nxt = "RL"[rand(2)]
                t = 0
            else
                nxt = "B"
            end
        end
        case nxt
        when "F"
            x += dx
            y += dy
        when "R"
            dx, dy = rot(dx, dy)
        when "B"
            x -= dx
            y -= dy
        when "L"
            dx, dy = revrot(dx, dy)
        end
        puts nxt
    end
    STDOUT.flush
}