A7769. Sequence

Little Petya likes to play very much. And most of all he likes to play the following game:

He is given a sequence of $N$ integer numbers. At each step it is allowed to increase the value of any number by $1$ or to decrease it by $1$ . The goal of the game is to make the sequence non-decreasing with the smallest number of steps. Petya is not good at math, so he asks for your help.

The sequence $a$ is called non-decreasing if $a_{1}<=a_{2}<=...<=a_{N}$ holds, where $N$ is the length of the sequence.

The first line of the input contains single integer $N$ ( $1<=N<=5000$ ) — the length of the initial sequence. The following $N$ lines contain one integer each — elements of the sequence. These numbers do not exceed $10^{9}$ by absolute value.

Output one integer — minimum number of steps required to achieve the goal.