10 Given that $f(x)$ is a function defined on $\mathbf{R}$, $f(1)=1$ and for any $x \in$ $\mathbf{R}$, we have
$$
\begin{array}{l}
f(x+5) \geqslant f(x)+5 \\
f(x+1) \leqslant f(x)+1 .
\end{array}
$$

If $g(x)=f(x)+1-x$, then $g(2002)=$