table = []
Ha,Wa = input().split()
Hb,Wb = input().split()
Hc,Wc = input().split()
table = [(Ha,Wa,"A"),(Hb,Wb,"B"),(Hc,Wc,"C")]

table.sort(key=lambda x:x[1])
table.reverse()
table.sort(key=lambda x:x[0])
table.reverse()
for _ in table:
    print(_[2])