Problem:
 Score : 200 points    Problem Statement Given is a sequence of N integers A_1, \ldots, A_N .  Find the (multiplicative) inverse of the sum of the inverses of these numbers, \frac{1}{\frac{1}{A_1} + \ldots + \frac{1}{A_N}} .      Constraints  1 \leq N \leq 100  1 \leq A_i \leq 1000         Input Input is given from Standard Input in the following format:  N  A_1  A_2  \ldots  A_N       Output Print a decimal number (or an integer) representing the value of \frac{1}{\frac{1}{A_1} + \ldots + \frac{1}{A_N}} .  Your output will be judged correct when its absolute or relative error from the judge's output is at most 10^{-5} .        Sample Input 1 2
10 30      Sample Output 1 7.5  \frac{1}{\frac{1}{10} + \frac{1}{30}} = \frac{1}{\frac{4}{30}} = \frac{30}{4} = 7.5 .  Printing 7.50001 , 7.49999 , and so on will also be accepted.       Sample Input 2 3
200 200 200      Sample Output 2 66.66666666666667  \frac{1}{\frac{1}{200} + \frac{1}{200} + \frac{1}{200}} = \frac{1}{\frac{3}{200}} = \frac{200}{3} = 66.6666... .  Printing 6.66666e+1 and so on will also be accepted.       Sample Input 3 1
1000      Sample Output 3 1000  \frac{1}{\frac{1}{1000}} = 1000 .  Printing +1000.0 and so on will also be accepted.

Solution (Python):
import sys


def input():
    return sys.stdin.readline()[:-1]


def main():
    n = int(input())
    a = [int(i) for i in input().split()]

    ans = 0
    for i in a:
        ans += 1/i
    print(1/ans)


if __name__ == '__main__':
    main()

Solution (Python):
import sys

def input():
    return sys.stdin.readline().rstrip()

if __name__ == "__main__":
    n = int(input())
    al = list(map(int, input().split()))

    l = [1.0 / a for a in al]
    print(1.0 / sum(l))

Solution (Python):
N = int(input())
A = list(map(int, input().split()))
ans = 0

for v in A:
    ans += 1/v

print(1/ans)

Solution (Python):
N = int(input())
A = list(map(int,input().split()))
tmp = 0
for i in range(N):
    tmp += 1.0/A[i]
res = 1.0 / tmp
print(res)

Solution (Python):
n=int(input())
a=[1/int(i) for i in input().split()]
print(1/sum(a))

Solution (Python):
n = int(input())
a = list(map(int, input().split()))

ans = 0

for i in range(n):
    ans += 1 / a[i]

print(1 / ans)

Solution (Python):
n = int(input())
ss = sum([1/int(i) for i in input().split()])
print(1/ss)

Solution (Python):

n = int(input())
a_list = list(map(int, input().split()))

ans = 0
for i in range(n):
    ans += 1/a_list[i]
    
print(1/ans)

Solution (Python):
a = []
n = int(input())
a = list(map(int, input().split()))
s = 0
for i in range(n):
  s += 1/a[i]

print(1/s)

Solution (Python):
N = int(input())
As = list(map(int, input().split()))
r = 1/sum(map(lambda A: 1/A, As))
print(r)

Solution (Python):
N = int(input())
A = list(map(int, input().split()))
res = 0
for i in range(N):
  res += 1 / A[i]
print(1 / res)

Solution (Python):
n = int(input())
a = list(map(int, input().split()))
s = 0.0
for i in a:
    s += 1 / i
print(1/s)

Solution (Python):
n = int(input())
a = list(map(int,input().split()))
c = 0
for i in a:
  c += 1 / i
print(1/c)

Solution (Python):
N = int(input())
A = list(map(int, input().split()))
gokei = 0
for i in range(N):
    gokei += 1 / A[i]
print(1/gokei)

Solution (Python):
def main():
    n=int(input())
    aa=map(int, input().split())
    s=0
    for a in aa:
        s+=1/a
    print(1/s)
main()

Solution (Python):
n = int(input())
a = list(map(int, input().split()))
revsum = sum([1/i for i in a])
print(1/revsum)

Solution (Python):

n = int(input())
A = list(map(int, input().split()))

x = 0
for a in A:
    x += 1/a

print (1 / x)

Solution (Python):
N = int(input())
A = list(map(int, input().split()))
c = 0
for a in A:
    c += 1/a
print(1/c)

Solution (Python):
n = int(input())
a = list(map(int, input().split()))

s = 0.0
for i in range(n):
    s += 1/a[i]

print(1/s)

Solution (Python):
n = int(input())
li = list(map(int,input().split()))
su = 1
for i in li:
    su *= i
seki = 0
for i in li:
    seki += su//i
print(su/seki)

Solution (Python):


def readInts():
  return [int(s) for s in input().split(" ")]

def main():
  N = readInts()[0]
  A = readInts()

  ans = 1
  for a in A:
    ans *= a
  den = 0
  for a in A:
    den += ans // a
  print(ans / den)

if __name__ == "__main__":
  main()

Solution (Python):
N = int(input())
A = [int(_) for _ in input().split()]

print(sum([1/a for a in A])**(-1))

Solution (Python):
N = int(input())
A = list(map(int, input().split()))

temp = 0
for i in A:
    temp += 1 / i
print(1 / temp)

Solution (Python):
n = int(input())
print(1 / sum(1 / e for e in map(int, input().split())))

Solution (Python):
N = int(input())
A = list(map(int, input().split()))

ansinv = 0.0

for a in A:
    ansinv += 1 / a

print(1 / ansinv)

Solution (Python):
n=int(input())
a=list(map(int,input().split()))
s=0
for i in range(n):
    s+=1/a[i]
print(1/s)

Solution (Python):
N = int(input())
A = list(map(int, input().split()))
count = 1
for i in range(N):
  count *= A[i]
x = 0
for i in range(N):
  x += count//A[i]
print(count/x)

Solution (Python):
N = int(input())
a = list(map(int, input().split()))
ans = 0
for i in a:
    ans += (1 / i)
print((1 / ans))

Solution (Python):
n = int(input())
a = [int(i) for i in input().split()]
s = 0
for i in a:
    s += 1/i
print(1/s)

Solution (Python):
n=int(input())
*a,=map(int,input().split())
ans=0
for i in a:
  ans+=1/i
print(1/ans)

Solution (Python):
N=int(input())
A=list(map(int,input().split()))
total=0
for i in range(N):
    total+=(1/A[i])

print(1/total)

Solution (Python):
n = int(input())
l = list(map(int, input().split()))

a = 0
for i in l:
    a += 1/i

print(1/a)

Solution (Python):
n=int(input())
A=[int(o) for o in input().split()]
ans=0
for num in A:
    ans+=1/num

print(1/ans)

Solution (Python):
n = int(input())
a = list(map(int,input().split()))
ans = 0
for N in range(n):
        ans += 1 / a[N]
print(1 / ans)

Solution (Python):
N = int(input())
A = list(map(int, input().split()))
print(1/sum(map(lambda x:1/x, A)))

Solution (Python):



import sys

input = sys.stdin.readline

def main():
    n = int(input())
    A = map(int, input().split())

    sum = 0
    for a in A:
        sum += 1 / a
    print(1/sum)

main()

Solution (Python):
n,*A=list(map(int,open(0).read().split()))

print(1/sum([1/a for a in A]))

Solution (Python):
n=int(input())
a=[1/int(i) for i in input().split()]
print(1/sum(a))

Solution (Python):
N = int(input())
lst = list(map(int, input().split()))
s = 0
for elem in lst:
    s+= 1/ elem
print(1/s)

Solution (Python):
n = int(input())
a = [int(i) for i in input().split()]

s = 0
for i in range(n):
    s += 1/a[i]

print(1/s)

Solution (Python):
n=int(input())
a=list(map(int,input().split()))

ans=0
for i in a:
    ans+=1/i

print(1/ans)

Solution (Python):
def foo(a) :
  return 1/sum(1/x for x in a)
n = int(input())
a = list(map(int, input().split()))
print(foo(a))

Solution (Python):
n=int(input())
s=0.0
p=input().rstrip().split(' ')
for i in range(0,len(p)):
    s+=(1/int(p[i]))
print(1/s)

Solution (Python):
n = int(input())

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

s = 0

for i in a:
    s += 1/i

print(1/s)

Solution (Python):
N = int(input())
A = list(map(int, input().split()))
wa = 0

for i in range(len(A)):
    wa += 1./A[i]

print(1./wa)

Solution (Python):
n = int(input())
a = list(map(int, input().split()))
ss = 0
for i in range(n):
    ss += 1/a[i]
print(1/ss)

Solution (Python):
N = int(input())
A = list(map(int,input().split()))
s = 0
for i in A:
    s += 1 / i
print(1 / s)

Solution (Python):
N = int(input())
A = list(int(i) for i in input().split())
ans = 0
for i in range(N):
    ans += 1/A[i]
print(1/ans)

Solution (Python):
n = int(input())
*a, = map(int, input().split())
ans = 0
for i in range(n):
    ans += 1/a[i]

print(1/ans)

Solution (Python):
n = int(input())
a = map(int, input().split(" "))

print(1/sum(list(map(lambda x: 1/x, a))))

Solution (Python):
N=int(input())
A = list(map(int, input().split())) 
sum_=0
for a in A:
  sum_ += 1/a

print(1/sum_)

Solution (Python):
n = int(input())
a = list(map(int, input().split()))
s = 0
for i in a:
    s += (1 / i)
print(1 / s)

Solution (Python):
n = int(input())
a = list(map(int, input().split()))
ans = 0
for i in a:
    ans += 1/i
print(1/ans)

Solution (Python):
N = int(input())
print(1/sum([1/int(x) for x in input().split()]))

Solution (Python):
N = int(input())
A = list(map(int, input().split()))
ans = 1/sum([1/a for a in A])
print(ans)

Solution (Python):
class Solution:
    def main(self):
        N = int(input())
        A = list(map(int, input().split()))
        cum = 0
        for i in range(N):
            cum += 1/A[i]

        print(1/cum)


if __name__ == '__main__':
    Solution().main()

Solution (Python):
N = int(input())
A = list(map(int,input().split(' ')))
iA = [1/a for a in A]
ians = sum(iA)
print(1/ians)

Solution (Python):
input();print(1/sum([1/i for i in list(map(int,input().split()))]))

Solution (Python):
n = int(input())
a = list(map(int,input().split()))
ls = []
for i in range(n):
    ls.append(1/a[i])
    
print(1/sum(ls))

Solution (Python):
n = int(input())
li = list(map(int, input().split()))
b = 0
for i in li:
    b += 1 / i
print(1 / b)

Solution (Python):



import array
from bisect import *
from collections import *
import fractions
import heapq
from itertools import *
import math
import random
import re
import string
import sys

N = int(input())
As = list(map(int, input().split()))

mul = 1
for a in As:
    mul *= a

s = 0
for a in As:
    s += mul // a

print("{:.15f}".format(mul / s))

Solution (Python):
n = int(input())
a = list(map(int, input().split()))

ans = 0
for i in a:
    ans += 1 / i
print(1 / ans)

Solution (Python):
N = int(input())
astr = input().split()
A = [int(d) for d in astr]

s = 0
for a in A:
    s += 1/a
print(1/s)

Solution (Python):
n = int(input())
a = list(map(int, input().split()))
ans = 0
for i in a: ans += 1/i
print(1/ans)

Solution (Python):
n = int(input())
a = list(map(int, input().split()))

result = 0
for i in range(n):
    result += 1/a[i]

print(1/result)

Solution (Python):
N = int(input())
A = map(int, input().split())
rev_ans = 0
for a in A:
    rev_ans += 1 / a
ans = 1 / rev_ans
print(ans)

Solution (Python):
N = int(input())
A = [int(i) for i in input().split()]
ans = 0
for a in A:
    ans += 1/a
print(1/ans)

Solution (Python):
n = int(input())
a = list(map(int,input().split()))
count = 0
for i in range(n):
    count = count + 1/a[i]
print(1/count)

Solution (Python):
N = int(input())
a = list(map(int, input().split()))

ans = 0
for i in range(N):
    ans += 1/a[i]

print(1/ans)

Solution (Python):
n=int(input())
a=list(map(int, input().split()))

a_sum=0
for i in range(n):
    a_sum+=1/a[i]
print(1/a_sum)

Solution (Python):
N = int(input())
a_array = map(int,input().split())

a_sum = 0
for a in a_array:
    a_sum += (1/a)

print(1/a_sum)

Solution (Python):
n=int(input())
a=list(map(int,input().split()))
print(1/sum(1/a[i] for i in range(n)))

Solution (Python):
N = int(input())
A = list(map(int, input().split()))
s = 0.0
for a in A:
  s += 1/a
print(1/s)

Solution (Python):
def main(sample_file = ''):

    """ convenient functions
    
    
    
    
    
    """

    """convenient decorator
    
    
        
        
        
        
        
        
        
        
        
        
    """
    
    
    import sys
    sys.setrecursionlimit(10**7)
    from itertools import accumulate, combinations, permutations, product 
    
    from math import factorial, ceil, floor, sqrt
    def factorize(n):
        """return the factors of the Arg and count of each factor
        
        Args:
            n (long): number to be resolved into factors
        
        Returns:
            list of tuples: factorize(220) returns [(2, 2), (5, 1), (11, 1)]
        """
        fct = []  
        b, e = 2, 0  
        while b * b <= n:
            while n % b == 0:
                n = n // b
                e = e + 1
            if e > 0:
                fct.append((b, e))
            b, e = b + 1, 0
        if n > 1:
            fct.append((n, 1))
        return fct
    def combinations_count(n, r):
        """Return the number of selecting r pieces of items from n kinds of items.
        
        Args:
            n (long): number
            r (long): number
        
        Raises:
            Exception: not defined when n or r is negative
        
        Returns:
            long: number
        """
        
        if n < 0 or r < 0:
            raise Exception('combinations_count(n, r) not defined when n or r is negative')
        if n - r < r: r = n - r
        if r < 0: return 0
        if r == 0: return 1
        if r == 1: return n
        numerator = [n - r + k + 1 for k in range(r)]
        denominator = [k + 1 for k in range(r)]
        for p in range(2,r+1):
            pivot = denominator[p - 1]
            if pivot > 1:
                offset = (n - r) % p
                for k in range(p-1,r,p):
                    numerator[k - offset] /= pivot
                    denominator[k] /= pivot
        result = 1
        for k in range(r):
            if numerator[k] > 1:
                result *= int(numerator[k])
        return result
    def combinations_with_replacement_count(n, r):
        """Return the number of selecting r pieces of items from n kinds of items allowing individual elements to be repeated more than once.
        
        Args:
            n (long): number
            r (long): number
        
        Raises:
            Exception: not defined when n or r is negative
        
        Returns:
            long: number
        """
        if n < 0 or r < 0:
            raise Exception('combinations_with_replacement_count(n, r) not defined when n or r is negative')
        elif n == 0:
            return 1
        else:
            return combinations_count(n + r - 1, r)
    from bisect import bisect_left, bisect_right
    from collections import deque, Counter, defaultdict 
    from heapq import heapify, heappop, heappush, heappushpop, heapreplace,nlargest,nsmallest 
    from copy import deepcopy, copy 
    import operator
    from operator import itemgetter 
    
    
    from functools import reduce, lru_cache
    def chmin(x, y):
        """change minimum
        if x > y, x = y and return (x, True).
        convenient when solving problems of dp[i]
        
        Args:
            x (long): current minimum value
            y (long): potential minimum value
        
        Returns:
            (x, bool): (x, True) when updated, else (x, False)
        """
        if x > y:
            x = y
            return (x, True)
        else:
            return (x, False)
    def chmax(x, y):
        """change maximum
        if x < y, x = y and return (x, True).
        convenient when solving problems of dp[i]
        
        Args:
            x (long): current maximum value
            y (long): potential maximum value
        
        Returns:
            (x, bool): (x, True) when updated, else (x, False)
        """
        if x < y:
            x = y
            return (x, True)
        else:
            return (x, False)

    from fractions import gcd 
    def gcds(numbers):
        return reduce(gcd, numbers)
    def lcm(x, y):
        return (x * y) // gcd(x, y)
    def lcms(numbers):
        return reduce(lcm, numbers, 1)
    def make_divisors(n, reversed=False):
        """create list of divisors
        
        Args:
            number (int): number from which list of divisors is created
            reversed (bool, optional): ascending order if False. Defaults to False.
        
        Returns:
            list: list of divisors
        """
        divisors = set()
        for i in range(1, int(n**0.5)+1):
            if n % i == 0:
                divisors.add(i)
                divisors.add(n//i)
        return sorted(list(divisors),reverse=reversed)
    
    
    
    INF = 10 ** 18
    MOD = 10 ** 9 + 7
    modpow = lambda a, n, p = MOD: pow(a, n, p) 
    def modinv(a, p = MOD):
        
        
        return modpow(a, p-2, p)
    def modinv_list(n, p = MOD):
        if n <= 1:
            return [0,1][:n+1]
        else:
            inv_t = [0,1]
            for i in range(2, n+1):
                inv_t += [inv_t[p % i] * (p - int(p / i)) % p]
            return inv_t
    def modfactorial_list(n, p = MOD):
        if n == 0:
            return [1]
        else:
            l = [0] * (n+1)
            tmp = 1
            for i in range(1, n+1):
                tmp = tmp * i % p
                l[i] = tmp
            return l
    def modcomb(n, k, fac_list = [], p = MOD):
        
        
        from math import factorial
        if n < 0 or k < 0 or n < k: return 0
        if n == 0 or k == 0: return 1
        if len(fac_list) <= n:
            a = factorial(n) % p
            b = factorial(k) % p
            c = factorial(n-k) % p
        else:
            a = fac_list[n]
            b = fac_list[k]
            c = fac_list[n-k]
        return (a * modpow(b, p-2, p) * modpow(c, p-2, p)) % p
    def modadd(a, b, p = MOD):
        return (a + b) % MOD
    def modsub(a, b, p = MOD):
        return (a - b) % p
    def modmul(a, b, p = MOD):
        return ((a % p) * (b % p)) % p
    def moddiv(a, b, p = MOD):
        return modmul(a, modpow(b, p-2, p))

    class UnionFindTree:
        """union find tree class
        TODO: fix this description...
        how to use (example):
        >>  uf = UnionFindTree(N) 
        >>  if uf.find_root(a) == uf.find_root(b):
        >>      do something
        >>  else:
        >>      do something
        >>      uf.unite(a, b)
        """
        def __init__(self, N):
            self.root = [-1] * (N+1)
            self.rank   = [0]  * (N+1)
            self.connected_num = [1] * (N+1)
    
        def find_root(self,x):
            root = self.root
            while root[x] != -1:
                x = root[x]
            return x
    
        def unite(self,x,y):
            root = self.root
            rank = self.rank
            connected_num = self.connected_num
            find_root = self.find_root
    
            rx = find_root(x)
            ry = find_root(y)
            if rx != ry:
                if rank[rx] < rank[ry]:
                    root[rx] = ry
                    rx,ry = ry,rx
                else:
                    if rank[rx] == rank[ry]:
                        rank[rx] += 1
                    root[ry] = rx       
                connected_num[rx] += connected_num[ry]

    
    
    
    
    

    def BellmanFord(N, M, ABC, vertex_start, vertex_end, value_if_inf = -1, find_shortest = False):
        """to calculate furthest or shortest length between vertex_start and vertex_end using BellmanFord algorithm
        
        Args:
            N (int): number of vertices
            M (int): number of edges
            ABC (list): [(ai, bi, ci) for _ in range(N)] where i-th edge is directed from vertex ai to vertex bi and the length is ci 
            vertex_start (int): start vertex. usually use 0.
            vertex_end (int): end vertex. usually use N-1.
            value_if_inf (int or string as you like, optional): value you want when the furthest (or shortest) distance is infinite (or -infinite). Defaults to -1.
            find_shortest (bool, optional): choose False to find furthest path. Defaults to False.
        
        Returns:
            int or string: normally int (but can be str if you set value_if_inf to str)
            
        Example:
                N, M, P = R()
                ABC = [R() for _ in range(M)]
                ABC = [(a-1, b-1, c-P) for a, b, c in ABC]
                print(BellmanFord(N, M, ABC, 0, N-1, value_if_inf = 'inf'))

        """

        def make_reachable_list(N, M, ABC, vertex_start, vertex_end):
            reachable_to_direct = defaultdict(list)
            reachable_from_direct = defaultdict(list)
            reachable_from_start = [False] * N
            reachable_to_end = [False] * N
            reachable_from_start[vertex_start] = True
            reachable_to_end[vertex_end] = True
            reachable_from_both_sides = [False] * N
            dfs_from_start = []
            dfs_to_end = []
            for a, b, c in ABC:
                reachable_to_direct[a].append(b)
                reachable_from_direct[b].append(a)
                if a == vertex_start:
                    dfs_from_start.append(b)
                    reachable_from_start[b] = True
                if b == vertex_end:
                    dfs_to_end.append(a)
                    reachable_to_end[a] = True
            while dfs_from_start:
                v = dfs_from_start.pop()
                for i in reachable_to_direct[v]:
                    if not reachable_from_start[i]:
                        reachable_from_start[i] = True
                        dfs_from_start.append(i)
            while dfs_to_end:
                v = dfs_to_end.pop()
                for i in reachable_from_direct[v]:
                    if not reachable_to_end[i]:
                        reachable_to_end[i] = True
                        dfs_to_end.append(i)
            for i in range(N):
                reachable_from_both_sides[i] = reachable_from_start[i] and reachable_to_end[i]
            return reachable_from_both_sides
        
        reachable_from_both_sides = make_reachable_list(N, M, ABC, vertex_start, vertex_end)
        
        if find_shortest:
            dist = [INF for i in range(N)]
        else:
            dist = [-INF for i in range(N)]
        
        dist[vertex_start] = 0
        for i in range(N):
            updated = False
            for a, b, c in ABC:
                if not reachable_from_both_sides[a]:
                    continue
                elif find_shortest:
                    update_condition = dist[a] + c < dist[b]
                else:
                    update_condition = dist[a] + c > dist[b]
                if dist[a] != INF and update_condition:
                    dist[b] = dist[a] + c
                    updated = True
                    if i == N-1:
                        return value_if_inf
            if not updated:
                break
        return dist[vertex_end]

    """ initialize variables and set inputs
    
        
        
    
        
        
        
        
        
        
        
    
        
        
        
        
    
        
        
    """

    
    r = lambda: sys.stdin.readline().strip()
    r_int = lambda: int(r())
    R = lambda: list(map(int, r().split()))
    Rmap = lambda: map(int, r().split())
    Rfloat = lambda: list(map(float, r().split()))
    Rtuple = lambda: tuple(map(int, r().split()))

    """ how to treat input
    
    
    
    
    
    
    
    """

    
    if sample_file:
        sys.stdin = open(sample_file)
        
    
    

    N = int(r())
    A = R()
    ans = 0
    for a in A:
        ans += 1/a
    print(1/ans)
    
    
    

    
    
    

    """memo: how to use defaultdict of list
    
    Dic = defaultdict(list)
    
    Dic[x].append(y)
    
    for k, v in Dic.items():
    """
    
    """memo: how to solve binary problems
    
    >>> a = 5
    >>> bin_str_a = format(a, '
    >>> print(bin_str_a)
    0b0101 
    """
    
    """memo: how to solve the problem
    creating simple test/answer
    greed
    simple dp
    graph
    """

if __name__ == '__main__':
    main()

Solution (Python):
from functools import reduce
from operator import mul

n = int(input())
a = list(map(int, input().split()))

p = reduce(mul, a)

y = 0
for aa in a:
    y += p // aa

print(p / y)

Solution (Python):
N = int(input())
A = list(map(int,input().split()))

q = 0
for a in A :
    q += 1/a

print(1/q)

Solution (Python):
N = int(input())
A = [int(i) for i in input().split()]

s = 0
for a in A:
    s += 1/a
print(1/s)

Solution (Python):
n = int(input())
a = list(map(int, input().split()))
r = 0
for i in a:
    r += (1/i)
ans = 1/r
print(ans)

Solution (Python):
n = int(input())
a = list(map(int, input().split()))
b = [0]*n
for i in range(n):
    b[i]=1/a[i]
print(1/sum(b))

Solution (Python):
import sys
def get_array(): return list(map(int , sys.stdin.readline().strip().split()))
def get_ints(): return map(int, sys.stdin.readline().strip().split())
def input(): return sys.stdin.readline().strip()

n=int(input())
Arr=get_array()
total=0
for i in Arr:
  total+=(1/i)
ans=1/total
print(ans)

Solution (Python):
N = int(input())
a = list(map(int, input().split()))
tmp = 1
for i in range(N):
    tmp *= a[i]

s = 0
for i in range(N):
    s += tmp // a[i]

print(tmp / s)

Solution (Python):
N = int(input().strip())
A = list(map(int, input().strip().split()))

b = 0
for a in A: b += 1 / a

print(1 / b)

Solution (Python):
from sys import stdin
N = int(stdin.readline().rstrip())
data = [int(x) for x in stdin.readline().rstrip().split()]
ans = 0
for i in data:
    ans += (1/i)
print(1/ans)

Solution (Python):
n = int(input())
A = list(map(int, input().split()))
ans = 0

for i in range(n):
    ans += 1/A[i]

ans = 1/ans
print(ans)

Solution (Python):
N = input()
A = map(float, raw_input().split())

print "%.10f"%(1/sum(1/a for a in A))

Solution (Python):
N = int(input())
A = list(map(int, input().split()))

sum_Ainv = 0
ans = 0

for i in range(N):
    sum_Ainv += (1 / A[i])

ans = 1 / sum_Ainv

print(ans)

Solution (Python):
import sys
input = sys.stdin.readline

def main():
  n = int(input())
  alist = list(map(int, input().split()))
  ans = 0
  for a in alist:
    ans += 1/a
  print('%.10f' % (1/ans))


if __name__ == '__main__':
  main()

Solution (Python):
n = int(input())
ls = list(map(lambda x: 1/int(x), input().split()))
print(1/sum(ls))

Solution (Python):
import sys, re, os
from collections import deque, defaultdict, Counter
from math import ceil, sqrt, hypot, factorial, pi, sin, cos, radians
from itertools import permutations, combinations, product, accumulate
from operator import itemgetter, mul
from copy import deepcopy
from string import ascii_lowercase, ascii_uppercase, digits
from fractions import gcd
 
def input(): return sys.stdin.readline().strip()
def INT(): return int(input())
def MAP(): return map(int, input().split())
def S_MAP(): return map(str, input().split())
def LIST(): return list(map(int, input().split()))
def S_LIST(): return list(map(str, input().split()))

sys.setrecursionlimit(10 ** 9)
INF = float('inf')
mod = 10 ** 9 + 7

n = INT()
A = LIST()
s = 0
for a in A:
    s += (1/a)
print(1/s)

Solution (Python):
n = int(input())
a = list(map(int,input().split()))

b = 0
for i in range(n):
    b += 1/a[i]

print(1/b)

Solution (Python):
N = int(input())
A = list(map(int, input().split()))

total = 0
for a in A:
    total += 1/a

print(1/total)

Solution (Python):
n = int(input())
nums =  list(map(int, input().split() ))

ans = 0
for i in range(n):
	ans += 1 / nums[i]
ans = 1 / ans
print(ans)

Solution (Python):
N = int(input())
A = list(map(int,input().split()))
s = 1
for i in range(N):
    s *= A[i]
su = 0
for i in range(N):
    su += s//A[i]
print(s/su)

Solution (Python):
N = int(input())
a = list(map(int, input().split()))

b = []
for i in range(N):
    b.append(1/a[i])

print(1/sum(b))

Solution (Python):

n = int(input())
a = list(map(int, input().split()))
p = 1
for x in a:
    p *= x
s = 0
for x in a:
    s += p // x
print(p / s)

Solution (Python):
N = int(input())

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

tmp = 0

for i in range(len(A)):
    tmp += (1/A[i])

print(1/tmp)

Solution (Python):
n = int(input())
a = list(map(int, input().split()))
s = sum(map(lambda x:1 / x, a))
print(1 / s)

Solution (Python):
n = int(input())
A = list(map(int, input().split()))

t = 0
for i in range(n):
    t += 1/A[i]

print(1/t)

Solution (Python):
N = int(input())
A = list(map(int,input().split()))

print(1/sum(1/a for a in A))

Solution (Python):
N = int(input())
A = list(map(int, input().split()))
ans = 0
for i in range(N):
    ans += 1/A[i]

print(1/ans)

Solution (Python):
n = int(input())
a = list(map(int, input().split()))
s = 0
for x in a:
    s += 1 / x
print(1 / s)

Solution (Python):
import sys
sys.setrecursionlimit(10**7)
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x) - 1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def II(): return int(sys.stdin.readline())
def SI(): return sys.stdin.readline().strip()
INF = 10 ** 18
MOD = 10 ** 9 + 7

debug = True


def dprint(*objects):
    if debug == True:
        print(*objects)

def solve():
    N = II()
    a_list = LI()

    ans = 0
    for a in a_list:
        ans += 1/a
    print(1/ans)

solve()

Solution (Python):




n = int(input())
a = list(map(int,input().split()))

sum = 0

for i in range(n):
    sum = sum + (1 / a[i])

ans = 1 / sum


print(ans)

Solution (Python):
input()

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

s=0
for it in a:
    s+=1/it
print(1/s)

Solution (Python):

import sys
import math
from bisect import bisect_left
from bisect import bisect_right
import collections
import copy
import heapq
from collections import defaultdict
from heapq import heappop, heappush
import itertools
input = sys.stdin.readline






















def inputInt(): return int(input())
def inputMap(): return map(int, input().split())
def inputList(): return list(map(int, input().split()))

def main():
	N = inputInt()
	A = inputList()

	ans = 0
	for i in A:
		tmp = 1/i
		ans += tmp

	print(1/ans)


if __name__ == "__main__":
	main()

Solution (Python):



import sys
import math
import bisect
sys.setrecursionlimit(1000000000)
from heapq import heappush, heappop,heappushpop
from collections import defaultdict
from itertools import accumulate
from collections import Counter
from collections import deque
from operator import itemgetter
from itertools import permutations
mod = 10**9 + 7
inf = float('inf')
def I(): return int(sys.stdin.readline())
def LI(): return list(map(int,sys.stdin.readline().split()))

n = I()
a = LI()
x = 1
for i in range(n):
    x *= a[i]
s = []
for i in range(n):
    s.append(x//a[i])
print(x/sum(s))

Solution (Python):
n = int(input())
dat = list(map(int, input().split()))
res = 0
for i in range(len(dat)):
    res += 1 / dat[i]
res = 1 / res
print(res)

Solution (Python):
n = int(input())
a = list(map(int, input().split()))
sum = 0

for i in a:
    sum += 1/i

print(1/sum)

Solution (Python):
N = int(input())
A = list(map(int,input().split()))

inv = 0
for a in A:
    inv += 1/a
res = 1/inv
print(res)

Solution (Python):
N = int(input())
A = [int(i) for i in input().split()]

ans = 0
for i in range(N):
    ans += 1/A[i]

print(1/ans)

Solution (Python):
N=int(input())
A=list(map(int,input().split()))

sum=0
for a in A:
    sum += 1.0 / a

ans = 1.0 / sum
print(ans)

Solution (Python):
import math
import sys
import queue
from collections import Counter
from itertools import accumulate
from fractions import gcd
from functools import reduce


def lcm(a, b):
    return a * b // gcd(a, b)

def combination_count(n, r):
    return math.factorial(n) // (math.factorial(n - r) * math.factorial(r))

def permutations_count(n, r):
    return math.factorial(n) // math.factorial(n - r)

sys.setrecursionlimit(10000)

mod = 1000000007

"""

a = 100
b = 0.987654321
print("{0:06d}-{1:6f}".format(a,b))
000100-0.987654


char_list = list("abcd") 



    = sys.stdin.readline().rstrip()
    = list(sys.stdin.readline().rstrip())


    = int(sys.stdin.readline())
    = map(int, sys.stdin.readline().split())
    = list(map(int, sys.stdin.readline().split()))
    = [list(map(int,list(sys.stdin.readline().split()))) for i in range(N)]
"""

if __name__ == "__main__":
    N = int(sys.stdin.readline())
    L = list(map(int, sys.stdin.readline().split()))
    B = 0
    for l in L:
        B +=  1 / l

    print(1 / B)