In the task said, that the polygon is convex, but in the
sample input it isn't so.

> In the task said, that the polygon is convex, but in the
> sample input it isn't so.

Why do you think so ?
It is a rectangle.

> > In the task said, that the polygon is convex, but in
the
> > sample input it isn't so.
>
> Why do you think so ?
> It is a rectangle.

How can it be rectangle?
x1=10.74646;y1=4.237533;
x2=0;y2=3;
x3=4;y3=3;
x4=4;y4=0;
This figure is not rectangle!