h1,w1=list(map(int,input().split(" ")))
h2,w2=list(map(int,input().split(" ")))
h3,w3=list(map(int,input().split(" ")))
res=[["A",h1,w1],["B",h2,w2],["C",h3,w3]]
res.sort(key=lambda x:(x[1],-x[2]),reverse=True)
for r in res:
    print(r[0])