Smallest Enclosing Sphere

There are $N$ points in three-dimensional space. Find the sphere of smallest radius that contains all of them, and print that radius. A point that lies on the surface of the sphere counts as contained.

The first line contains a positive integer $N$ ($1 \le N \le 1{,}000$).

Each of the next $N$ lines contains three integers $x$, $y$, $z$ separated by spaces, the coordinates of one point ($-1{,}000{,}000 \le x, y, z \le 1{,}000{,}000$).

The same coordinates may appear more than once.

On the first line, print the radius of the sphere rounded at the third decimal place, so that exactly two decimal places are shown.