A = list(map(int,input().split()))
B = list(map(int,input().split()))
C = list(map(int,input().split()))

dct = {"A":[A[0],A[1]], "B":[B[0],B[1]], "C":[C[0],C[1]]}
for k, v in sorted(dct.items(), key=lambda x: -x[1][0]):
    print(k)