h1,w1 = map(int,input().split())
h2,w2 = map(int,input().split())
h3,w3 = map(int,input().split())

a = [["A",h1,w1],["B",h2,w2],["C",h3,w3]]
b = sorted(a, key=lambda x:(x[1],-x[2]),reverse=True)

for c in b:
    print(c[0])