program Project1;

{$APPTYPE CONSOLE}

uses
  SysUtils;

   var
   i, j, m, n, maxa, x0, xn, x, p : integer;
   s : int64;
   l : real;
   a : array [1..10000] of integer;

begin
   readLn(n, m);
   maxa := 0;    s := 0;
   for i := 1 to n do
     begin
       readLn(l);
       a[i] := round(100*l);
       s := s + a[i];
       if maxa < a[i] then maxa := a[i];
     end;
   if s div m < 1 then writeLn('0.00')
   else
     begin
       if m = 1 then writeLn(maxa/100:10:2)
       else
         begin
           xn := s div m;
           x0 := 0;
           repeat
             p := 0;
             x := (xn+x0) div 3;
             for i := 1 to n do
               inc(p, a[i] div x);
             if p >= m then x0 := x
             else xn := x;
           until p = m;
           for i := xn downto x0 do
             begin
               p := 0;
               for j := 1 to n do
               inc(p, a[j] div i);
               if p = m then begin writeLn(i/100:0:2);  halt;  end;
             end;
         end;
     end;
end.