n=int(eval(input()))

lista=list(map(int,input().split()))

count=0

for a in lista:

  count+=1/a

print((1/count))
n=int(eval(input()))

l=list(map(int,input().split()))

sum=0

for ll in l:

  sum+=1/ll

print((1/sum))
n = int(eval(input()))
lista = list(map(int, input().split()))
count = 0
for a in lista:
    count += 1 / a
print((1 / count))

n = int(eval(input()))
l = list(map(int, input().split()))
sum = 0
for ll in l:
    sum += 1 / ll
print((1 / sum))

-lista = list(map(int, input().split())) -count = 0 -for a in lista: -    count += 1 / a -print((1 / count)) +l = list(map(int, input().split())) +sum = 0 +for ll in l: +    sum += 1 / ll +print((1 / sum))