题面Input a real number xxx (−105≤x≤105)(-10^5 \le x \le 10^5)(−105≤x≤105), output its cube square root with error less than 10−610^{-6}10−6 using newton-raphson algorithm.样例输入0 输出0.0000000000 输入-27.000000 输出-3.0000000000