Pasha will perfectly manage to study exactly \textbf{one} topic in mathematics before the exam, but there are many tasks on the exam and from different topics, so what to do?

Pasha has learned to change the topics of exam tasks. So he won't fail.

If the topic of the task is $a_i$, then in one operation Pasha can change the topic of the task in one of the following ways:
\begin{itemize}
\item $a_i:=a_i+1$;
\item $a_i:=a_i-1$.
\end{itemize}
In other words, in one operation Pasha can choose some element of the array and change it by one.

Pasha was lucky to find exam tickets in the e-learning system, there are a total of $n$ questions, each of which is characterized by a single number $a_i$. However, things are not so smooth, so to minimize the chance of getting caught, he must make the \textbf{minimum} possible number of operations.

Your task is to transform all tasks into tasks of one topic with the \textbf{minimum} number of operations.