题解 | #中彩票的的概率#

from functools import reduce
nums = input().split(' ')
prob = input().split(' ')
bought = input().split(' ')
dic = dict(zip(nums,prob))
numbers = list(map(lambda x:float(dic[x]),bought))
res = round(reduce(lambda x,y:x*y,numbers),3)
# reduce可以快速的将数组内所有元素按照第一个参数的运算规则进行归一化
print(res)