Square

The square in Vasya's hometown is a rectangle of n \times m meters. On the occasion of the city's anniversary, it was decided to pave the square with square granite slabs. Each slab has a size of k \times k meters. The anniversary is very close, but the workers still could not determine the minimum number of slabs required to cover the square. Vasya immediately came up with a solution for this task. Can you solve it?

It is allowed to cover an area larger than the square, but the square itself must be completely covered. Granite slabs cannot be broken or cut; they can only be used whole. The edges of the slabs must be parallel to the edges of the square.