#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;
}