{ Автор: Винарский Евгений <[email protected]>, 112 гр.}
program t_11_17(input,output);
var x,y: real;
  function sh(z: real): real;
    begin
      z:=exp(z);
      sh:=(z-1/z)/2;
    end;
  function tg(z: real): real;
    begin
      tg:=sin(z)/cos(z);
    end;
begin
  read(x);
  y:=sh(x)*tg(x+1)-sqrt(tg(2+sh(x-1)));
  write(y);
end.