CF13C.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.

小Petya非常喜欢玩游戏。他最喜欢玩下面这个游戏：

给定一个长度为 $N$ 的整数序列。在每一步中，允许将任意一个数的值加 $1$ 或减 $1$。游戏的目标是以最少的操作步数，使该序列变为非递减序列。Petya 不擅长数学，因此他向你求助。

若对长度为 $N$ 的序列 $a$ 满足 $a_1 \le a_2 \le \ldots \le a_N$，则称其为非递减序列。

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 109 by absolute value.

输入的第一行包含一个整数 $N$（$1 \leq N \leq 5000$）—— 表示初始序列的长度。接下来的 $N$ 行每行包含一个整数 —— 即序列的元素。这些数的绝对值不超过 $10^9$。

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

输出一个整数——达成目标所需的最少步数。