Also, here is what is often stupid about yichus:
Anything which is more than 3-4 generations, is pretty meaningless.
If you go back 10 generations, you have 1024 ancestors at that level. Meaning you have 1024 great-great-great-great-great-great-great-great-grandparents.
Go back just a few more and it is totally viral. 30 generation is 1 Billion ancestors at that level.
Now look at the descendant side. Assuming 5 life kids per generation, someone 5 generations ago would have 3125 descendants. So you are one of them. Yay!!
So when someone tells you they are descended from the shach, don’t be too impressed. If they say from rashi, just say “me too, howdy cuz”.