§ 30. Month, computation. A number of months after or before a certain
day shall be computed by counting such number of calendar months from
such day, exclusive of the calendar month in which such day occurs, and
shall include the day of the month in the last month so counted having
the same numerical order in days of the month as the day from which the
computation is made, unless there be not so many days in the last month
so counted, in which case the period computed shall expire with the last
day of the month so counted.