Description

Write a program to compute the value of the following piecewise function $y=f(x)$. The result should be rounded to three decimal places.

$y=-x+2.5;$ $0≤x<5$
$y=2-1.5(x-3)(x-3);$ $5≤x<10$
$y=\frac{x}{2}-1.5;$ $10≤x<20$

Input Format

A floating-point number $N(0 ≤ N < 20)$.

Output Format

Output the value of the piecewise function corresponding to $N$: $f(N)$.
The result should be rounded to three decimal places.

1.0

1.500