You are given a binary string (i. e. 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.

Input

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.

Output

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.

Examples

Input


7 2
1100110


Output


16


Input


5 0
10010


Output


1


Input


8 1
10001000


Output


10


Input


10 8
0010011000


Output


1

Note

Some strings you can obtain in the first example:

  * to obtain 0110110, you can take the substring from the 1-st character to the 4-th character, which is 1100, and reorder its characters to get 0110; 
  * to obtain 1111000, you can take the substring from the 3-rd character to the 7-th character, which is 00110, and reorder its characters to get 11000; 
  * to obtain 1100101, you can take the substring from the 5-th character to the 7-th character, which is 110, and reorder its characters to get 101. 



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.
5 2
00011
 5 4
11011
 81 5
100000101000000011001101010100001010111000000110000000001000101101111000001000110
 4 3
1011
 47 25
11110011111001110100101010011000110111011011101
 291 159
011001110111110110001111000110001001111100010001011000110100110010001101100110111010101111100111110000110111001100111010001000011001010011011100101000101011010110010011010100100101111010111000001011110101001011101110100100111110011001101010001110110101010101100011101110111000011111011001110
 459 15
101010101010101010101010101010101010101010101111111111111111111111010101010101010101010101011111111111111111111101010101010101010101111111111111111111111101010101010101010111111111111111111111111101010101010101111111111111111111111111110110101010101011111111111111111111111111111001000111111111111111111111111111110000011111111111111111111111111111000001111111111111111111111111111100001111111111111111111111111111100111111111111111111111111111110111111111111
 105 58
110101000111100000011011011101110100001000110011010101100010111001011111010010111101011011010110011011110
 52 11
0110011111001000010000100010010001010100000100110100

10
 5
 187538
 4
 314445058
 1
 0
 132732930
 478323746

import sys
input = sys.stdin.readline

n, k = map(int, input().split())
mod = 998244353
s = list(input().rstrip())
l = n + 5
fact = [1] * (l + 1)
for i in range(1, l + 1):
    fact[i] = i * fact[i - 1] % mod
inv = [1] * (l + 1)
inv[l] = pow(fact[l], mod - 2, mod)
for i in range(l - 1, -1, -1):
    inv[i] = (i + 1) * inv[i + 1] % mod

def comb(n, r):
    return fact[n] * inv[r] % mod * inv[n - r] % mod if n >= r >= 0 else 0

x = [-1]
for i in range(n):
    if s[i] == "1":
        x.append(i)
x.append(n)
l = len(x) - 1
ans = 1
for i in range(1, len(x) - 1):
    xi = x[i]
    l = i - 1 if i < k else x[i - k] + 1
    for j in range(l, x[i + 1]):
        if xi == j:
            continue
        c = min(i - 1, k - 1)
        m = j - 1 - x[max(0, i - k)]
        ans += comb(m, c)
        ans %= mod
if len(x) - 2 < k:
    ans = 1
print(ans)