Let $f, g: R \rightarrow R$ be functions defined by $f(x)=\left\{\begin{array}{cc}{[x],} & x<0 \\ |1-x|, & x \geq 0\end{array}\right.$ and $g(x)=\left\{\begin{array}{cc}e^x-x, & x<0 \\ (x-1)^2-1, & x \geq 0\end{array}\right.$ where $[x]$ denote the greatest integer less than or equal to x . Then, the function fog is discontinuous at exactly