#include <bits/stdc++.h>

#include <atcoder/modint>
using namespace std;
using mint = atcoder::modint998244353;

mint res;
int main() {
	int n, m;
	cin >> n >> m;
	string x;
	cin >> x;
	vector<string> a(n);
	for(auto &s : a) cin >> s;
	mint cur = 1;
	for(int i = m - 1; i >= 0; --i) {
		if(x[i] == '1') res += cur;
		cur *= 2;
	}
	cout << (res + 1).val() << endl;
}