# 座標当てゲーム


def main():

    print("?", 0, flush=True)

    d = int(input())

    if d == 0:
        print("!", 0, flush=True)
        exit()

    print("?", d, flush=True)
    d2 = int(input())

    if d2 == 0:
        print("!", d, flush=True)
        exit()
    else:
        print("!", -d, flush=True)
        exit()
    


if __name__ == "__main__":
    main()