Begin
var x:=ReadReal();
var y:real;
if x<=-4 then
y:=0
else if (x>-4) and (x<=6) then
y:=sin(x) ** 2
else if (x>=6) and (x<=20) then
y:=x ** (3/2)
else if (x>20) then
y:= (sin(x) ** 2)/2;
y.Println;
End.
