var a: integer; b, c, d, e: real;
begin
  readln(b);
  c := 1;
  d := 1;
  e := 1;
  for a := 1 to 10 do
  begin
    e := -e * b;
    d := d + (a + 1) / (a + 2) * e;
  end;
  writeln(d:0:4);
end.