Goal
You are given N non-overlapping spheres, each centered at (x,y,z) with radiusr. In the same order as they are given, expand the radius of each sphere until it touches any of the other spheres.
Input
Line 1: The Number of spheres
Next N lines: x y z r for each sphere, space separated
Output
The sum of r^3 for all the spheres after expansion, rounded to the nearest integer.
Constraints
2≤ N ≤ 100
0≤x,y,z≤100
0<r≤100
