#include <iostream>


#include <string>


using namespace std;





const int P = 998244353, N = 1e4 + 10, M = 20;


int n, m;


string s;


int dp[1 << M];





int solve() {


	dp[0] = 1;


	for (int i = 0; i < n; i++) {


		for (int j = (1 << (m - 1)) - 1; j >= 0; j--) {


			int k = (j << 1) | (s[i] - '0');


			if (j != 0 || s[i] == '1')


				dp[k] = (dp[k] + dp[j]) % P;


		}


	}


	int ans = 0;


	for (int i = 0; i < (1 << m); i++) {


		ans = (ans + 1ll * i * dp[i]) % P;


	}


	return ans;


}


int solve2() {


	int ans = 0;


	for (int i = 0; i < (1 << n); i++) {


		int cnt = 0;


		int num = 0;


		for (int j = 0; j < n; j++) {


			if (i & (1 << j)) {


				num = num * 2 + (s[j] - '0');


				cnt++;


			}


		}


		if (cnt <= m)(ans += num) %= P;


	}


	return ans;


}





int main() {


	cin >> n >> m;


	cin >> s;


	if (n <= 20) {


		cout << solve2() << endl;


	}


	cout << solve() << endl;


	return 0;


}

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