A building measures 40′ x 70′ and has an eve height of 12′. How many sheets of drywall are needed to cover the walls? (note you are using 4′ x 8′ sheets of drywall)

A building measures 40′ x 70′ and has an eve height of 12′. How many sheets of drywall are needed to cover the walls? (note you are using 4′ x 8′ sheets of drywall)