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.

输入描述:

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.

输出描述:

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