The Best Subsequence || Find the minimum of special value of a subsequence

Choose k elements, keeping their original order, so that the sum of the absolute differences between adjacent chosen values is minimized.

This site's standard input/output format and supplementary bounds are as described in this problem.

输入格式

The first line contains n k (1≤n≤800, 1≤k≤n); the next line contains n integers, |arr[i]|≤10^9.

输出格式

Output the minimum special value.

样例 1

输入：

5 2
9 5 1 4 9

输出：

0

样例 2

输入：

6 3
9 5 1 4 9 100

输出：

5

样例 3

输入：

1 1
-3

输出：

0