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

def rotr(dx, dy) [-dy, dx] end
def rotl(dx, dy) [dy, -dx] end
def rcell(f, x, y, dx, dy)
    rx, ry = rotr(dx, dy)
    f[y + ry][x + rx]
end
def lcell(f, x, y, dx, dy)
    lx, ly = rotl(dx, dy)
    f[y + ly][x + lx]
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
            w[y + dy * d.succ][x + dx * d.succ] = WALL_CELL
            loop {
                flg = 0
                for2p(9..51,9..51) {|i,j|
                    next if f[i][j] != SPACE_CELL
                    next if w[i][j] == WALL_CELL
                    c = 0
                    [[-1,0],[1,0],[0,-1],[0,1]].each do |ii,jj|
                        c += 1 if f[i + ii][j + jj] == WALL_CELL || w[i + ii][j + jj] == WALL_CELL
                    end
                    if c >= 3
                        w[i][j] = WALL_CELL
                        flg = 1
                    end
                }
                break if flg == 0
            }
        end
        nxt = "F"
        rc =  rcell(f, x, y, dx, dy)
        lc =  lcell(f, x, y, dx, dy)
        if rc == UNKNOWN_CELL
            nxt = "R"
        elsif lc == UNKNOWN_CELL
            nxt = "L"
        else
            rw = rcell(w, x, y, dx, dy)
            lw = lcell(w, x, y, dx, dy)
            if d > 0
                if rw == WALL_CELL && lw == WALL_CELL
                    nxt = "F"
                elsif rw != WALL_CELL
                    nxt = "RRFFFF"[rand(5)]
                elsif lw != WALL_CELL
                    nxt = "LLFFFF"[rand(5)]
                else
                    nxt = "F"
                end
            else
                if rc == SPACE_CELL && lc == SPACE_CELL && rw != WALL_CELL && lw != WALL_CELL
                    nxt = "LRLRRL"[rand(4)]
                elsif rc == SPACE_CELL && rw != WALL_CELL
                    nxt = "R"
                else
                    nxt = "L"
                end
            end
        end
        
        if w[y][x] == WALL_CELL
            nx, ny = dx, dy
            a = []
            4.times do |i|
                tx, ty = x, y
                (1..20).each do 
                    tx += nx
                    ty += ny
                    break if f[ty][tx] == WALL_CELL
                    if f[ty][tx] == SPACE_CELL && w[ty][tx] != WALL_CELL
                        a << "FRLB"[i]
                        break
                    end
                end
                nx, ny = rotr(nx, ny)
            end
            if a.size > 0
                nxt = a[0]
            else
                nxt = "FRBL"[rand(4)]
            end
        end
        
        puts nxt
        case nxt
        when "F"
            x += dx
            y += dy
        when "R"
            dx, dy = rotr(dx, dy)
        when "L"
            dx, dy = rotl(dx, dy)
        when "B"
            x -= dx
            y -= dy
        end
    end
    STDOUT.flush
}