program formula5;

var x:real;

begin

read(x);

if (x <=9)and(x>=0) then

write(x)

else if x<0 then

write(x+2)

else

write(x-2)

end.

C++11:

static double Y(double X){

if(x<0) return x+2;

if(x>9) return x-2;

return x;

}