$$\left. \begin{array} { l } { 1 } \\ { C = \{ \quad \frac { y + 1 } { 3 y + 3 } , y \leq 1 } \end{array} \right.$$
$y\in (-\infty,-1)\cup (-1,1]\text{, }C=\frac{1}{3}\text{ and }a=1$
$a=1$
