Lines turned into Meshes - how to convert Meshes into polylines?

Hi everybody

I have exported a 3D network from small program “Pajek” into Rhino. Because of the previous problems with exporting it into Rhino directly (Exporting Pajek Network to Rhino - how to delete the edges and leave nodes only?) I did it through 3DS Max, then saved as .dwg and opened in AutoCAD , then saved it as .dwg 2010 version and then opened in Rhino with “double precision” option checked. And it worked - but now the network consist of the “meshes-lines” instead of just lines.

Therefore does anybody know how to convert these meshes into polylines?

It’s very important to have this model made in a simple manner, becuase it is being used further in operating a Robotic Arm.

Best regards,

The post can be closed. The command “ExtractWireframe” had sorted it out.