Blow weed everyday

Snoop and Dogg are two very lazy brothers. To teach them a lesson of responsibility, their mother has asked them to remove weed from their garden. Assume that the garden is a grid of $MxN$ dimensions. The garden has weed grown in $K$ of these grid cells. Because, the brothers are so lazy, Snoop will only clear one row of garden whereas Dogg will only clear one column of the garden. What is the max