#include <bits/stdc++.h>
using namespace std;
const long long inf = 0x3f3f3f3f3f3f3f3f;
const long long MAXN = 222222;
void print(vector<long long> v) {
  long long n = v.size();
  for (long long i = 0; i < n; i++) cout << v[i] << " ";
  cout << '\n';
}
long long power(long long a, long long b) {
  long long res = 1;
  while (b != 0) {
    if (b & 1) res = (res % 998244353 * a % 998244353);
    a = (a % 998244353 * a % 998244353) % 998244353;
    b /= 2;
  }
  return res % 998244353;
}
struct FenwickTree {
  vector<long long> bit;
  long long n;
  FenwickTree(long long n) {
    this->n = n;
    bit.assign(n, 0);
  }
  FenwickTree(vector<long long> a) : FenwickTree(a.size()) {
    for (size_t i = 0; i < a.size(); i++) add(i, a[i]);
  }
  long long sum(long long r) {
    long long ret = 0;
    for (; r >= 0; r = (r & (r + 1)) - 1) ret += bit[r];
    return ret;
  }
  long long sum(long long l, long long r) { return sum(r) - sum(l - 1); }
  void add(long long idx, long long delta) {
    for (; idx < n; idx = idx | (idx + 1)) bit[idx] += delta;
  }
};
FenwickTree bit(MAXN);
void update(long long &ans, long long cnt, long long i) {
  ans = (ans % 998244353 + (cnt % 998244353 * power(2, i)) % 998244353) %
        998244353;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  long long n, m;
  cin >> n >> m;
  string s1, s2;
  cin >> s1 >> s2;
  reverse(s1.begin(), s1.end());
  reverse(s2.begin(), s2.end());
  for (long long i = 0; i < m; i++) {
    bit.add(i, s2[i] - '0');
  }
  long long ans = 0;
  for (long long i = 0; i < min(n, m); i++) {
    if (s1[i] - '0') {
      update(ans, bit.sum(i, m + 5), i);
    }
  }
  cout << ans;
  return 0;
}
