from operator import mul

from functools import reduce





N = int(eval(input()))

if N == 1:

    ans = int(eval(input()))

    print(ans)

    exit()

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





upper = reduce(mul, lst_A)

lower = 0

for i in range(N):

    lst_tmp = lst_A[:i] + lst_A[i+1::]

    lower += reduce(mul, lst_tmp)

ans = upper / lower

print(ans)
N = int(eval(input()))

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

ans = 1 / sum(1 / x for x in lst_A)

print(ans)
from operator import mul
from functools import reduce

N = int(eval(input()))
if N == 1:
    ans = int(eval(input()))
    print(ans)
    exit()
lst_A = list(map(int, input().split()))
upper = reduce(mul, lst_A)
lower = 0
for i in range(N):
    lst_tmp = lst_A[:i] + lst_A[i + 1 : :]
    lower += reduce(mul, lst_tmp)
ans = upper / lower
print(ans)

N = int(eval(input()))
lst_A = list(map(int, input().split()))
ans = 1 / sum(1 / x for x in lst_A)
print(ans)

-from operator import mul -from functools import reduce - -if N == 1: -    ans = int(eval(input())) -    print(ans) -    exit() -upper = reduce(mul, lst_A) -lower = 0 -for i in range(N): -    lst_tmp = lst_A[:i] + lst_A[i + 1 : :] -    lower += reduce(mul, lst_tmp) -ans = upper / lower +ans = 1 / sum(1 / x for x in lst_A)