[Cases of] lashes [are judged] by three. In the name of R’ Yishmael they said: By twenty-three. The intercalating of the month is by three; the intercalating of the year is by three; [these are] the words of R’ Meir. Rabban Shimon ben Gamliel says: It is begun with three, discussed by five, and concluded by seven. If they concluded with three it is valid.