In this problem, there are conditional blocks. If your solution works correctly for certain constraints, it will receive a certain number of points. Note that each test is graded individually.

\begin{enumerate}
\item ($10$ points): $n=1$;
\item ($10$ points): $x=1$;
\item ($20$ points): $a_1=a_2=\dots=a_n$;
\item ($60$ points): without additional constraints.
\end{enumerate}