a) Prove that if a perfect cover has no fault-lines, where m, n are even, then 2n + 2m - 4 <= mn/2.

b)Prove that if a perfect cover has no fault-lines, where m is even and n is odd, then 2n+ (3/2)m - 4 <= mn/2.

Can someone show one of these, so I can get an idea on how to do the other. Thanks