There are a sufficient number of chess pieces in the box, A and B play a game of chess pieces, A sometimes takes 5 pieces each time, and sometimes 5-k pieces each time; B sometimes takes 7 pieces each time, and sometimes takes 7 pieces each time 7-k pieces (here 0<k<5). According to statistics, A has taken a total of 36 pieces, and B has taken a total of 40 times. As a result, the total number of chess pieces taken by the two is exactly equal. At least how many chess pieces are in the box.
盒中放有足够数量的棋子，甲、乙二人做取棋子游戏，甲有时每次取5枚，也有时每次取5-k枚；乙有时每次取7枚，也有时每次取7-k枚(这里0＜k＜5)．据统计，甲先后共取棋子36次，乙先后共取40次．结果两人所取出的棋子总数恰好相等．盒中至少有多少枚棋子．
<result>240</result>