program sinx(input,output);
label 1,9;
const pi=3.1415926;
var x,y:real; n:integer;
begin
 write('vvedite x '); read(x);
 n:=1; if x<0 then n:=-1;
 1:if abs(x)>2*pi then begin x:=abs(x)-2*pi; goto 1 end;
 if (x>=pi/2) and (x<=pi) then begin y:=n*cos(x-pi/2); goto 9 end
       else if (x>=pi)and(x<=1.5*pi) then begin y:=-n*sin(x-pi); goto 9 end
       else if (x>=1.5*pi)and(x<=2*pi) then begin y:=-n*cos(x-1.5*pi); goto 9 end;
  y:=n*sin(x);
  9: writeln('sin(x)=',y)
end.