/*路程s越远，每公里运费越低。标准如下：

s　　 d

s＜250km 　　 没有折扣

250≤s＜500　　 2

500≤s＜1000　　 5

1000≤s＜2000 8

2000≤s＜3000 10

s≥3000　　 15

设每公里，每吨货物的基本运费为p（price缩写），货物重量为w(weight)，距离为s，折扣为d(discount)，

则总运费f(freight的缩写)的计算公式为：f=p*w*s*(1-d)*/-* S walk farther, lower freight per kilometer. The following criteria:

s d

s <250km no discount

250 ≤ s <500 2

500 ≤ s <1000 5

1000 ≤ s <2000 8

2000 ≤ s <3000 10

s ≥ 3000 15

Let per kilometer per tonne of basic goods freight p (price abbreviation), cargo weight w (weight), a distance of s, discount for the d (discount),

The total freight f (freight acronym) is calculated as: f = p* w* s* (1-d)* /