def main():
    brothers = [list(map(int, input().split())) for _ in range(3)]
    brother_dict = {0: "A", 1: "B", 2: "C"}
    wonderful_order = sorted(range(3), key=lambda idx: (
        brothers[idx][0], -brothers[idx][1]), reverse=True)
    for order in wonderful_order:
        print(brother_dict[order])


if __name__ == "__main__":
    main()