Let $A=\{1,2,3, \ldots, 10\}$ and $f: A \rightarrow A$ be defined as $f(k)=\left\{\begin{array}{cc}k+1 & \text { if } k \text { isodd } \\ k & \text { if kis even }\end{array}\right.$ Then the number of possible functions $g: A \rightarrow$ A such that $g$ of $=f$ is
