B"You are given a binary string (i. xe2 x80 x89e. a string consisting of characters 0 and/or 1) s of length n . You can perform the following operation with the string s at most once: choose a substring (a contiguous subsequence) of s having exactly k characters 1 in it, and shuffle it (reorder the characters in the substring as you wish). Calculate the number of different strings which can be obtained from s by performing this operation at most once. The first line contains two integers n and k ( 2 <= n <= 5000 ; 0 <= k <= n ). The second line contains the string s of length n , consisting of characters 0 and/or 1. Print one integer -- the number of different strings which can be obtained from s by performing the described operation at most once. Since the answer can be large, output it modulo 998244353 . Some strings you can obtain in the first example: In the second example, k = 0 so you can only choose the substrings consisting only of 0 characters. Reordering them doesn't change the string at all, so the only string you can obtain is 10010. "...