This function finds the distance between two points.

Parameters:

• double x1 - x coordinate of first point.
• double y1 - y coordinate of first point.
• double z1 - z coordinate of first point.
• double x2 - x coordinate of second point.
• double y2 - y coordinate of second point.
• double z2 - z coordinate of second point.

Responds:

• TBD

Reports:

• TBD

Example:

• User sends: "fd 0 0 0 3 4 12"
• answer is 13