def main():
    d = {}
    l = []
    d["height"] = int(input())
    d["name"] = "A"
    l.append(d)
    d = {}
    d["height"] = int(input())
    d["name"] = "B"
    l.append(d)
    d = {}
    d["height"] = int(input())
    d["name"] = "C"
    l.append(d)
    l.sort(key=lambda d: -d["height"])
    for i in l:
        print(i["name"])


if __name__ == "__main__":
    main()