The root of a cubic equation#6356
After arriving in Italy, our heroes learned about mathematical competitions held among scholars during the Renaissance. They were particularly intrigued by the story of the contest between the mathematicians Fiore and Tartaglia, the essence of which was to find the roots of a cubic equation.
Please, write a program that finds the root of the cubic equation
It is known that the given equation has exactly one real root. You need to find it.
The input file contains four integers separated by spaces: , , , , -1000 \le A, B, C, D \le 1000.
Output the unique root of the equation with a precision of at least 10^{-5}.
Example 1
Example 2