Lowest points in a 3D grid

Hello,

I need to find the lowest points in a 3D grid. I have found e method but I would like to know if there is a shorter way and above all if there is a method that doesn't require the use of a component from an additional plug-in (in this case removeDuplicatePts of Kangaroo), that is to say I would like to use only GH standard components.

The grid that I use as example is the one of the 2 following images. Each "column" of points miss a different number of points starting from the bottom.

This is the method I have found

And a visualization of the result

I attach as well the GH definition.

lowestpointsina3Dgrid.gh

Thank you in advance.

Francesco