def js(a, b):
    if (a == 1 and b == 2 or a == 2 and b == 3 or a == 3 and b == 1):
        return 1
    else:
        return 0


a, b, c = map(int, input().split())
d, e, f = map(int, input().split())
a1 = 0
a2 = 0


a1 += js(a, d)+js(b, e)+js(c, f)
a2 += js(d, a)+js(e, b)+js(f, c)
if (a1 > a2):
    print("A")
elif (a1 == a2):
    print("C")
else:
    print("B")
# 1表示石头，2表示剪刀，3表示布
# 暴力算法，等会改