#region ZIPPER
using System;
using System.Collections.Generic;
using System.Collections;
using System.Linq;
using System.Text;
using System.Numerics;
using sc = Scanner;
class Program
{
static void Main(string[] args)
{
Solver solver = new Solver();
solver.Solve();
#if DEBUG
System.Console.WriteLine("続行するには何かキーを押してください...");
System.Console.ReadKey();
#endif
}
}
///
/// Java風のスキャナー,自作(某最速の人を参考)
///
public static class Scanner
{
public static string NextString()
{
string tmp = "";
while (true)
{
int readData;
string data;
readData = Console.Read();
if (readData == -1) //EOF
{
break;
}
data = char.ConvertFromUtf32(readData);
if (data == " " || data == "\n")
{
break;
}
tmp += data;
}
return tmp;
}
public static int NextInt()
{
string tmp = "";
while (true)
{
int readData;
string data;
readData = Console.Read();
if (readData == -1) //EOF
{
break;
}
data = char.ConvertFromUtf32(readData);
if (data == " " || data == "\n")
{
break;
}
tmp += data;
}
return int.Parse(tmp);
}
public static long NextLong()
{
string tmp = "";
while (true)
{
int readData;
string data;
readData = Console.Read();
if (readData == -1) //EOF
{
break;
}
data = char.ConvertFromUtf32(readData);
if (data == " " || data == "\n")
{
break;
}
tmp += data;
}
return long.Parse(tmp);
}
public static double NextDouble()
{
string tmp = "";
while (true)
{
int readData;
string data;
readData = Console.Read();
if (readData == -1) //EOF
{
break;
}
data = char.ConvertFromUtf32(readData);
if (data == " " || data == "\n")
{
break;
}
tmp += data;
}
return double.Parse(tmp);
}
public static string[] NextStrArray()
{
return Console.ReadLine().Split(' ');
}
public static int[] NextIntArray()
{
string[] s = NextStrArray();
int[] a = new int[s.Length];
for (int i = 0; i < a.Length; i++)
{
a[i] = int.Parse(s[i]);
}
return a;
}
public static long[] NextLongArray()
{
string[] s = NextStrArray();
long[] a = new long[s.Length];
for (int i = 0; i < a.Length; i++)
{
a[i] = long.Parse(s[i]);
}
return a;
}
public static double[] NextDoubleArray()
{
string[] s = NextStrArray();
double[] a = new double[s.Length];
for (int i = 0; i < a.Length; i++)
{
a[i] = double.Parse(s[i]);
}
return a;
}
}
#endregion ZIPPER
public class Solver
{
#region IGNORE_ME
public Solver()
{
//こんすとらくたん きにしなくてよろしい
}
#endregion IGNORE_ME
#region FIELD
#endregion FIELD
public void Solve()
{
int n = sc.NextInt();
long[] l = sc.NextLongArray();
long k = sc.NextLong();
double eps = 1.0/1000000000;
double low = 0;
double mid = 1;
double hi = 2 * 10000 + 1000; // seiyaku ni yoru max yori tyotto over
while ((hi-mid)/mid > eps)
{
mid = (low + hi) / 2;
if (canCut(l,mid,k))
{
low = mid;
}
else
{
hi = mid;
}
}
Console.WriteLine((low+hi)/2);
#if DEBUG
Console.WriteLine("");//local check
#endif
}
///
///ipponnatari s no nagasa de k hon kiretu
///
///
///
///
bool canCut(long[] l,double s, long k)
{
long countOfCut = 0;
for (int i = 0; i < l.Length; i++)
{
countOfCut += (long)(l[i]/s);
}
return countOfCut >= k ? true : false;
}
}