begin
var x := ReadReal;
var y := (2 * Tan(x) * Sin(x) + 1 / 4 * Sqrt(Abs(1 - Sqr(Sin(x)) * Tan(x /
((1 + x * x / 2) ** (1 / 3) + LogN(3, Abs(x)));
Print(y)
end.
begin
var x := ReadReal;
var y := (2 * Tan(x) * Sin(x) + 1 / 4 * Sqrt(Abs(1 - Sqr(Sin(x)) * Tan(x /
((1 + x * x / 2) ** (1 / 3) + LogN(3, Abs(x)));
Print(y)
end.