program s; //1161 stripies
var
  a:array [1..100] of integer;
  n,i,j,temp:integer;
  res:real;
begin
  read(n);
  for i:=1 to n do
     read(a[i]);
  for i:=1 to n-1 do
     for j:=1 to n-1 do
        if a[j]<a[j+1] then begin
           temp:=a[j];
           a[j]:=a[j+1];
           a[j+1]:=temp;
        end;
  res:=a[1];
  for i:=2 to n do
     res:=2*(sqrt(a[i]*res));
  if n=1 then write(a[1]) else
  write(res:0:2);
  end.