Grump and Wall

A president of a huge country built a wall around the country. The bricks are stacked one on top of the other in N columns .The walls were built unevenly, each column has different number of bricks stacked in it. He wants to make it even. He has allocated a budget of D dollars to make the walls even. We can remove a brick or add a brick to a wall. There are infinite bricks available. Cost of remov