def main():
    A = input()
    B = input()
    C = input()
    if A == "RED" and B == "RED":
        print("RED")           
    elif A == "RED" and C == "RED":
        print("RED")
    elif B == "RED" and C == "RED":
        print("RED")
    else:
        print("BLUE")


if __name__ == '__main__':
    main()