Gomti the Cow

Gomti is a hungry and lazy cow. Her master is fed up with her because she does nothing useful. So now he has thought of a new job for her, eating grass. She has a field in front of her with some weeds in it. Her job is to eat those weeds. But being lazy, she wants to do it as optimally as possible. For simplicity lets assume that the field in front of her is divided in M X N squares such that sh