import sys
sys.setrecursionlimit(10**7)

N=int(input())
seen=set()
def F():
    input()
    print("F")
def B():
    input()
    print("B")
def L():
    input()
    print("L")
def R():
    input()
    print("R")
def solve(x,y):
    seen.add((x,y))
    le=input()
    if le=="Merry Christmas!":
        exit()
    le=int(le)
    if not (x+1,y) in seen:
        seen.add((x+1,y))
        if le:
            print("F")
            solve(x+1,y)
            B()

    if (x,y-1) in seen and (x-1,y) in seen and (x,y+1) in seen:
        return
    print("L")
    le=input()
    if le=="Merry Christmas!":
        exit()
    le=int(le)
    if not (x,y+1) in seen:
        seen.add((x,y+1))
        if le:
            print("F")
            solve(x,y+1)
            B()

    if (x,y-1) in seen and (x-1,y) in seen:
        return
    print("L")
    le=input()
    if le=="Merry Christmas!":
        exit()
    le=int(le)
    if not (x-1,y) in seen:
        seen.add((x-1,y))
        if le:
            print("F")
            solve(x-1,y)
            B()
    
    if (x,y-1) in seen:
        return
    print("L")
    le=input()
    if le=="Merry Christmas!":
        exit()
    le=int(le)
    if not (x,y-1) in seen:
        seen.add((x,y-1))
        if le:
            print("F")
            solve(x,y-1)
            B()
print("F")
solve(0,0)