We build up a tower with a pile of stones. Each layer of the tower is exactly one piece of stone. We index the layers from top to bottom, so layer 1 is the top layer. The stone weight of the i-th layer is s. The tower will fall if there exists a layer i s.t. Dj=1 s; > s. For example, if the tower is built with 5 stones and the stone weight from top to bottom is 2,3,5, 9, 100, then the tower would fall because 9