Xiaohu placed the chess pieces on the grid points of the 19*19 Go board, and first placed them into a rectangular solid lattice. Then add 45 pieces of chess pieces again, just in time put into the solid lattice of bigger rectangle with side unchanged. So how many chess pieces did Xiaohu use at most?
小虎在19*19的围棋盘的格点上摆棋子，先摆成了一个长方形的实心点阵．然后再加上45枚棋子，就正好摆成-边不变的较大的长方形的实心点阵．那么小虎最多用了多少枚棋子．
<gadget id="calculator">15 * 19</gadget>
<output>285</output>

<result>285</result>