065. Intersection of Two Lines
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

When performing calculations on linear equations, finding the intersection point of two lines is a very common task. Write a program that takes two linear equations in the form of $$$y=mx+b$$$ and outputs the $$$x$$$ coordinate at which the two lines intersect.

Input

The first line contains two floating point values representing the $$$m$$$ and $$$b$$$ values of the first linear equation respectively. The second line contains the two variables corresponding to the $$$m$$$ and $$$b$$$ variables of the second linear equation.

Output

A single floating point value that represents the $$$x$$$ coordinate at which the two lines intersect.

Example
Input
5 3
-6 -20
Output
-2.090909090909091
Note

Assume that all test cases contain lines that do intersect.