#include <bits/stdc++.h>
using namespace std;
void input(long long int n, long long int a[]) {
  for (long long int i = 0; i < n; ++i) cin >> a[i];
}
long long int bin_expo(long long int A, long long int B, long long int M) {
  long long int res = 1LL;
  while (B > 0) {
    if (B % 2 == 1) {
      res = (res * A) % M;
    }
    A = (A * A) % M;
    B = B / 2;
  }
  return res;
}
long long int gcd(long long int a, long long int b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
long long int lcm(long long int a, long long int b) {
  return (a * b) / gcd(a, b);
}
long double distance(long long int x1, long long int y1, long long int x2,
                     long long int y2) {
  return sqrt(pow(x2 - x1, 2) + pow(y2 - y1, 2) * 1.0);
}
long long int power(long long int x, long long int y, long long int m) {
  if (y == 0) return 1;
  long long int p = power(x, y / 2, m) % m;
  p = (p * p) % m;
  return (y % 2 == 0) ? p : (x * p) % m;
}
long long int getDigits(long long int x) {
  long long int sum = 0;
  while (x) {
    sum += x % 10;
    x /= 10;
  }
  return sum;
}
long long int tmp[200005] = {0};
int main() {
  ios_base::sync_with_stdio(0);
  long long int n, m;
  cin >> n >> m;
  string s1, s2;
  cin >> s1 >> s2;
  long long int id = 0;
  vector<long long int> v;
  for (int i = n - 1; i >= 0; i--) {
    if (s1[i] == '1') {
      v.push_back(id);
    }
    id++;
  }
  id = 0;
  for (int i = m - 1; i >= 0; i--) {
    if (s2[i] == '1') {
      tmp[id] = 1;
    }
    id++;
  }
  for (int i = id - 2; i >= 0; i--) {
    tmp[i] += tmp[i + 1];
  }
  long long int ans = 0;
  for (auto it : v) {
    ans += ((power(2, it, 998244353) % 998244353) * (tmp[it])) % 998244353;
    ans = ans % 998244353;
  }
  cout << ans << endl;
  return 0;
}
