beecrowd | 2517
# PoGro Challenge

**Timelimit: 1**

By Ricardo Oliveira, UFPR Brazil

PoGro is a famous brand of hi-tech digital cameras. This year, PoGro is promoting the P*oGro Challenge*! In this challenge, each participant must jump from the top of a building and land safely at a specific point in the ground, using only an hang-glider.

Consider that the top of the building is at the point (0,**C**) of the Cartesian plane, and the landing point is at (**x _{F}**, 0). In order to complete the challenge, the participant must follow strictly the path defined by the parabola given by the function f(x) = -x²/

The staff put a PoGro camera at the position (**x _{c}**,

However, the staff is having trouble to determine what will be the distance between the camera and the participant in the moment the photo will be taken (exemplified by the dotted line in the figure). Given the path of the participant and the camera’s position, determine the distance between both of them in the moment the photo will be taken!

First line of each test case contains three integers **A**, **B**, **C** (1 ≤ **A**, **B**, **C** ≤ 200) describing the path. Second line contains two integers **x _{c}** and

It is guaranteed that f(**x _{F}**) = 0. Also, please notice that f(x) is such that the function is decreasing for x ≥ 0, and that the height of the building is positive.

The input ends with end-of-file (EOF).

For each test case, print a line containing the distance between the camera and the participant in the moment the photo is taken. Round and print the answer with exactly 2 decimal places.

Input Sample | Output Sample |

10 2 5 |
1.14 |