13:I[87,["736","static/chunks/89fc4f0e-9e200ae6a0166583.js","401","static/chunks/363642f4-32903b9154b7835a.js","153","static/chunks/153-58eddeb032cc4608.js","131","static/chunks/131-05ce00cfd760e12b.js","87","static/chunks/87-b76b60eef573119a.js","286","static/chunks/app/problem/%5Bid%5D/page-45cf3875257fc32e.js"],"Header"] 14:I[1742,["736","static/chunks/89fc4f0e-9e200ae6a0166583.js","401","static/chunks/363642f4-32903b9154b7835a.js","153","static/chunks/153-58eddeb032cc4608.js","131","static/chunks/131-05ce00cfd760e12b.js","87","static/chunks/87-b76b60eef573119a.js","286","static/chunks/app/problem/%5Bid%5D/page-45cf3875257fc32e.js"],"ProblemView"] 15:T703,

Let's call beauty of an array $$$b_1, b_2, \ldots, b_n$$$ ($$$n \gt 1$$$) — $$$\min\limits_{1 \leq i \lt j \leq n} |b_i - b_j|$$$.

You're given an array $$$a_1, a_2, \ldots a_n$$$ and a number $$$k$$$. Calculate the sum of beauty over all subsequences of the array of length exactly $$$k$$$. As this number can be very large, output it modulo $$$998244353$$$.

A sequence $$$a$$$ is a subsequence of an array $$$b$$$ if $$$a$$$ can be obtained from $$$b$$$ by deletion of several (possibly, zero or all) elements.

Input

The first line contains integers $$$n, k$$$ ($$$2 \le k \le n \le 1000$$$).

The second line contains $$$n$$$ integers $$$a_1, a_2, \ldots, a_n$$$ ($$$0 \le a_i \le 10^5$$$).

Output

Output one integer — the sum of beauty over all subsequences of the array of length exactly $$$k$$$. As this number can be very large, output it modulo $$$998244353$$$.

Array Beauty

Examples