A person who had his head and most of his body inside the succah and his table inside the house —- Beis Shammai invalidate [the succah] and Beis Hillel validate it.  Said Beis Hillel to Beis Shammai, “Did it not happen that the elders of Beis Shammai and the elders of Beis Hillel went to visit R’ Yochanan son of the Choranite and found him sitting with his head and most of his body inside the succah and his table within the house, and they said nothing to him?”  Beis Shammai replied to them, “Is that [your] proof? Actually, they said to him, `If this is how you have [always] conducted yourself, [then] you have never in your life fulfilled the mitzvah of succah.’ ”