Album duplication

I have just migrated from Classic to LR CC. In the left tab I have as the 'root' album/folder "Migrated Lightroom Catalog-3-2-v13". Within that I also have a album "Lightroom Catalog-3-2-v13" and another just called "Lightroom".  The latter have differing anumber of photos in them.

Why do I have these folders and can I safely delete the latter two? 

Thanks