# HW = [list(i, *list(map(int, input().split()))) for i in range(3)]
HW = [list(map(int, input().split())) for i in range(3)]
HW = [(i, *x) for i, x in enumerate(HW)]

HW = sorted(HW, key=lambda x: (x[1], -x[2]))[::-1]

for i, _, _ in HW:
    print("ABC"[i])