var x, a, b, c, res: integer;
begin
  readln(x);
  if x mod 2 = 0 then
    res := 2 * x
  else begin
    c := x mod 10;
    b := (x div 10) mod 10;
    a := x div 100;
    res := c * 100 + b * 10 + a;
  end;
  writeln(res);
end.