#include <bits/stdc++.h>
using namespace std;
const long long int infinity = 9e18;
bool compare(int a, int b) { return a > b; }
bool compare1(pair<int, int> a, pair<int, int> b) { return a.first > b.first; }
bool compare2(pair<int, int> a, pair<int, int> b) {
  return a.second < b.second;
}
long long int Npower(long long int a, long long int b) {
  long long int product = 1;
  while (b) {
    if (b & 1) {
      product = product * a;
    }
    a = a * a;
    b = b >> 1;
  }
  return product;
}
long long int power(long long int a, long long int b, long long int md) {
  long long int product = 1;
  while (b) {
    if (b & 1) {
      product = ((product % md) * (a % md)) % md;
    }
    a = ((a % md) * (a % md)) % md;
    b = b >> 1;
  }
  return product % md;
}
bool isprime(long long int n) {
  if (n < 2) return 0;
  long long int i = 2;
  while (i * i <= n) {
    if (n % i == 0) return 0;
    i++;
  }
  return 1;
}
long long int GCD(long long int a, long long int b) {
  return b == 0 ? a : GCD(b, a % b);
}
long long int LCM(long long int a, long long int b) {
  return (a / GCD(a, b)) * b;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n, m;
  cin >> n >> m;
  string s1, s2;
  cin >> s1 >> s2;
  if (n > m) {
    while (s2.size() < n) {
      s2 = '0' + s2;
    }
  } else if (n < m) {
    while (s1.size() < m) {
      s1 = '0' + s1;
    }
  }
  n = max(n, m);
  m = n;
  vector<long long int> count(n, 0);
  count[0] = (int)(s2[0] == '1');
  for (int i = 1; i < n; i++) {
    count[i] = count[i - 1] + (int)(s2[i] == '1');
  }
  long long int total = 0;
  for (int i = 0; i < n; i++) {
    if (s1[i] == '1')
      total = (total + count[i] * power(2, n - 1 - i, 998244353)) % 998244353;
  }
  cout << total;
  return 0;
}
