Devu and Perfume

There is a haunted town called HauntedLand. The structure of HauntedLand can be thought of as a grid of size n * m. There is a house in each cell of the grid. Some people have fled from their houses because they were haunted. '.' represents a haunted house whereas '*' represents a house in which people are living. One day, Devu, the famous perfumer came to town with a perfume whose smell can hypn