Actually, I used two steps. 1. Take the subset of months without a globally unique day? (Bernard doesn't know the answer) 2. Of the subset of months without a

Actually, I used two steps. 1. Take the subset of months without a globally unique day? (Bernard doesn't know the answer) 2. Of the subset of months without a globally unique day, is there a globally unique day within that subset? (Bernard knows the answer, and therefore so does Albert)