import sys

sys.setrecursionlimit(10 ** 6)
stdin = sys.stdin

ni = lambda: int(ns())
na = lambda: list(map(int, stdin.readline().split()))
ns = lambda: stdin.readline().strip()
nsa = lambda: list(stdin.readline().split())
ntp = lambda: tuple(map(int, stdin.readline().split()))
mod = 10 * 9 + 7
inf = 2 << 60

# 2021/05/11

HWdict = {}
HWdict[ntp()] = 'A'
HWdict[ntp()] = 'B'
HWdict[ntp()] = 'C'
HW = []
for a in HWdict.keys():
    HW.append(a)

HW.sort(key = lambda x: x[1])
HW.sort(reverse = True, key = lambda x: x[0])

for b in HW:
    print(HWdict[b])