import sys
import collections

def navi(y,x,dy,dx,path):
    move = []
    ty = -1
    tx = -1
    while path:
        ty,tx = path.pop()
        if y+dy == ty and x+dx==tx:
            move += ['F']
        elif y-dy == ty and x-dx==tx:
            move += ['B']
        elif y-dx == ty and x+dy==tx:
            move += ['L','F']
        elif y+dx == ty and x-dy==tx:
            move += ['R','F']
    return move

def accessible(sy,sx,ty,tx,maze):
    visited = [[False for j in range(40)] for i in range(40)]
    path = [[[] for j in range(40)] for i in range(40)]
    visited[sy][sx] = True
    dq = collections.deque()
    dq.append((sy,sx))
    D = [(1,0),(-1,0),(0,1),(0,-1)]
    while dq:
        y,x = dq.popleft()
        if y==ty and x ==tx:
            return path[ty][tx]
        for dy,dx in D:
            if 0<=y+dy<40 and 0<=x+dx<40 and not visited[y+dy][x+dx]:
                dq.append((y+dy,x+dx))
                visited[y+dy][x+dx] = True
                path[y+dy][x+dx] = path[y][x][:]+[(y,x)]
    return []


maze = [[0 for j in range(40)] for i in range(40)]
maze[19][19] = 1
posx = 19
posy = 19
dx = 0
dy = -1
tx = 19
ty = 19
path = []
move = []
while True:
    s = input()
    if s == 'Merry Christmas!':
        exit()
    s = int(s)
    if s > 17:
        print('F')
        sys.stdout.flush()
    elif s == 0:
        maze[posy+dy][posx+dx] = -1
        print('L')
        sys.stdout.flush()
    else:
        for i in range(1,s+1):
            maze[posy+dy*i][posx+dx*i] = 1
        if move:
            print(move.pop())
            sys.stdout.flush()
        else:
            i = 0
            j = 0
            while not path:
                path = accessible(posy,posx,i,j,maze)
                j += 1
                if j == 40:
                    j = 0
                    i += 1
            move = navi(posy,posx,dy,dx,path)
            print(move.pop())
            sys.stdout.flush()