Reference for Sukkah 64:21

הא גופא קשיא אמרת נשרו רוב עליו כשר והדר תני ובלבד שתהא עבותו קיימת כיון דנתרי להו תרי עבות היכי משכחת לה

But is not this self-contradictory? You said that if the majority of its leaves fell off it is valid and then it is stated, "provided that its plaited quality remains." But since two [of the three leaves] have fallen off, how is it possible to have it "avot"?

Jastrow