The Circumference of the Circle

To calculate the circumference of a circle seems to be an easy task - if you know its diameter. But what if you don't?

You are given the coordinates of three non-collinear points on the plane.

Your job is to calculate the circumference of the unique circle that passes through these three points.

Input

Contains multiple test cases. Each test case consists of one line containing six real numbers x[1], y[1], x[2], y[2], x[3], y[3], representing the coordinates of the three points. The diameter of the circle determined by the three points will never exceed a million.

Output

For each test case, print one line containing one real number - the circumference of the circle defined by three points. The circumference must be printed with two decimal digits.

Examples