abc = "ABC"
hw = [list(map(int, input().split())) + [i] for i in range(3)]
hw.sort(reverse = True)
if hw[0][0] == hw[2][0]:
    hw.sort(key = lambda x:x[1])
elif hw[0][0] == hw[1][0]:
    if hw[0][1] > hw[1][1]:
        hw[0][1], hw[1][1] = hw[1][1], hw[0][1]
elif hw[2][0] == hw[1][0]:
    if hw[1][1] > hw[2][1]:
        hw[2][1], hw[1][1] = hw[1][1], hw[2][1]
for _, _, i in hw:
    print(abc[i])