购买书籍的最小价格

print"请输入要购买的数量"#提示信息
amount=input()#amount为用户要购买的书的数量
(big_amount,small_amount)=divmod(amount,10)#将购买量除余求得结果

if(small_amount==1):#购买余数为1时最小特例部分的价钱，下同
    money=1*8
elif(small_amount==2):
    money=2*8*0.95
elif(small_amount==3):
    money=3*8*0.9
elif(small_amount==4):
    money=4*8*0.8
elif(small_amount==5):
    money=5*8*0.75
elif(small_amount==6):
    money=5*8*0.75+8
elif(small_amount==7):
    money=5*8*0.75+2*8*0.95
elif(small_amount==8):
    money=4*8*0.8*2
elif(small_amount==9):
    money=5*8*0.75+4*8*0.8
elif(small_amount==10):
    money=5*8*0.75*2
else:money=0

money=money+5*8*0.75*2*big_amount#总的价钱等于商值的价钱加上特例部分的价钱
print"最少话费：",money