For a restaurant promotion, spend over 100 yuan (cash part) to return one coupon, spend over 200 yuan (cash part) to return 2 coupons, and so on, the face value of each coupon is 50 yuan. The rules for using coupons are as follows: 1 coupon can be used for a purchase of 100 yuan, 2 coupons can be used for a purchase of 200 yuan, and so on. If Mr. Zhang has tasted the dishes worth 2,000 yuan in the restaurant successively, how much cash should he spend at least.
某饭店促销，消费满100元(现金部分)返一张优惠卷，满200元(现金部分)返2张优惠卷，依此类推，每张优惠卷面值为50元．优惠卷使用规则为：满100元可用1张优惠卷，满200元可用2张优惠卷，依此类推．张先生先后品尝该饭店价值2000元的菜品，则他至少消费现金多少元．
<gadget id="calculator">2_000 / 200</gadget>
<output>10</output>

<gadget id="calculator">10 * 150</gadget>
<output>1_500</output>

<result>1_500</result>