Ha = int(input())
Hb = int(input())
Hc = int(input())
lst = [Ha,Hb,Hc]
lst2 = sorted(lst,reverse = True)
dic = {Ha:"A",Hb:"B",Hc:"C"}
ans1 = dic[lst2[0]]
ans2 = dic[lst2[1]]
ans3 = dic[lst2[2]]
print(ans1)
print(ans2)
print(ans3)