with Ada.Text_IO, Ada.Integer_Text_IO, Ada.Float_Text_IO;
 use Ada.Text_IO, Ada.Integer_Text_IO, Ada.Float_Text_IO;

procedure main is
   R: Integer;
   Pi: Float;
begin
   Pi := 3.14159;
   get(R);
   put(Float(R) * 2.0 * Pi, 0, 2, 0);
end main;