import sys

input = sys.stdin.readline

sys.setrecursionlimit(10 ** 7)

 

import numpy as np

N = int(eval(input()))

A = np.array(input().split(),np.int32)

 

answer = 1/(1/A).sum()

print(answer)
n = eval(input())

r = 0

for s in input().split():

    r +=1/int(s)

print((1/r))
import sys

input = sys.stdin.readline
sys.setrecursionlimit(10**7)
import numpy as np

N = int(eval(input()))
A = np.array(input().split(), np.int32)
answer = 1 / (1 / A).sum()
print(answer)

n = eval(input())
r = 0
for s in input().split():
    r += 1 / int(s)
print((1 / r))

-import sys - -input = sys.stdin.readline -sys.setrecursionlimit(10**7) -import numpy as np - -N = int(eval(input())) -A = np.array(input().split(), np.int32) -answer = 1 / (1 / A).sum() -print(answer) +n = eval(input()) +r = 0 +for s in input().split(): +    r += 1 / int(s) +print((1 / r))