What is the fine-grained topic of the following text: During the time of the Beis Hamikdash, on the second day of Succos, Motzaei Yom Tov Rishon shel Succos (right after the first day of Succos was over), the entire Jewish nation, anashim, nashim, v’taf (men, women, and children) gathered in the Beis Hamikdash for the mitzvah of Hakhel. Only return the topic.
The mitzvah of Hakhel in Beis Hamikdash during Succos