C. Array Beautytime limit per test5 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputLet's call beauty of an array b_1, b_2, \ldots, b_n (n > 1)  — \min\limits_{1 \leq i < 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.InputThe 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).OutputOutput 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.ExamplesInput
4 3
1 7 3 5
Output
8Input
5 5
1 10 100 1000 10000
Output
9NoteIn the first example, there are 4 subsequences of length 3 — [1, 7, 3], [1, 3, 5], [7, 3, 5], [1, 7, 5], each of which has beauty 2, so answer is 8.In the second example, there is only one subsequence of length 5 — the whole array, which has the beauty equal to |10-1| = 9.
4 3
1 7 3 5

8
['dp', '*2500']