import math
import sys
def S(): return sys.stdin.readline().rstrip()
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int, sys.stdin.readline().rstrip().split())
def LI(): return list(map(int, sys.stdin.readline().rstrip().split()))
def LS(): return list(sys.stdin.readline().rstrip().split())

x = []
h, w = MI()
x.append([-h, w, 'A'])
h, w = MI()
x.append([-h, w, 'B'])
h, w = MI()
x.append([-h, w, 'C'])

x_s = sorted(x, key=lambda x:(x[0], x[1]))
for i in range(3):
    print(x_s[i][2])