theprof00 on 14 April 2015
It's not the days with 18 or 19 because bernard would know right away.
may july and august all share days with each other 1 for 1.
June shares one day with august, the 17th.
Albert has no idea with only the month, and he assumes that Bernard can't know either.
Bernard, knowing that Albert knows he doesn't know, now knows the month.
