program PKU1064;
{$S-,Q-,R-,I-}

const maxn = 10001;

type integer = longint;

var n, m, l, r: integer;
    a: array[1..maxn] of integer;

procedure prepare;
var i: integer;
    j: double;
begin
  read(n, m); r := 1;
  for i := 1 to n do begin
    read(j);
    a[i] := round(j * 100);
    if a[i] > r then r := a[i];
  end;
end;

function calc(c: integer): integer;
var k, i: integer;
begin
  if c = 0 then calc := m + 1 else begin
    k := 0;
    for i := 1 to n do begin
      k := k + a[i] div c;
      if k >= m then break;
    end;
    calc := k;
  end;
end;

procedure main;
var mid: integer;
begin
  l := 0;
  while l < r do begin
    mid := (l + r + 1) shr 1;
    if calc(mid) >= m then l := mid else r := mid - 1;
  end;
  writeln(l / 100:1:2);
end;

begin
  prepare;
  main;
end.

#include "iostream"
using namespace std;
int n,k;
int a[10100];
bool check(int mid)
{
int sum=0,i;
if(mid==0)return 0;
for(i=1; i <= n; ++i)
{
   sum+=a[i]/mid;
   if(sum >= k)return 1;
}
return 0;
}
int erfen(int MIN,int MAX)
{
int mid;
while(MIN <= MAX)
{
   mid=(MIN+MAX)/2;
   if(check(mid))
   { MIN=mid+1; }
   else
    MAX=mid-1;
}
return MAX;
}
int main()
{
int max,i;
double num,ans;
while(scanf("%d%d",&n,&k)!=EOF)
{
   max=0;
   for(i=1; i <= n; ++i)
   {
    scanf("%lf",&num);
    a[i]=(int)(100*num+0.3); 
    if(max<a[i])max=a[i];
   }
   ans=double(erfen(1,max))/100;
    printf("%.2lf\n",ans);
}
return 0;
}