def main():
    A = input()
    B = input()
    C = input()

    balloon_colors = {
        "RED": 0,
        "BLUE": 0
    }

    balloon_colors[A] += 1
    balloon_colors[B] += 1
    balloon_colors[C] += 1

    if balloon_colors["RED"] >= 2:
        print("RED")
    else:
        print("BLUE")


if __name__ == '__main__':
    main()