#include <bits/stdc++.h>
using namespace std;
long long int mod = 998244353;
long long int INF = 1000000000000000000;
long long int powmod(long long int a, long long int b) {
  long long int res = 1;
  a %= mod;
  assert(b >= 0);
  for (; b; b >>= 1) {
    if (b & 1) res = res * a % mod;
    a = a * a % mod;
  }
  return res;
}
long long int gcd(long long int a, long long int b) {
  return b ? gcd(b, a % b) : a;
}
const long long int MAXN = 300005;
void magic(int n, int *ar) {
  set<int> s;
  map<int, int> m;
  for (int i = 0; i < n; i++) s.insert(ar[i]);
  int size = 0;
  for (set<int>::iterator it = s.begin(); it != s.end(); it++) {
    m[*it] = size++;
  }
  for (int i = 0; i < n; i++) ar[i] = m[ar[i]];
}
bool present(string s, string r) {
  size_t found = s.find(r);
  if (found != string::npos) {
    return 1;
  }
  return 0;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int t = 1;
  while (t--) {
    long long int n, m, k = 0, sum = 0, y = 1, cnt = 0, res = INF, flag = 0,
                        ans = 0;
    cin >> n >> m;
    string a, b;
    cin >> a >> b;
    long long int pre[m];
    pre[0] = 1;
    for (int i = (1); i < (m); i++) {
      if (b[i] == '1')
        pre[i] = pre[i - 1] + 1;
      else
        pre[i] = pre[i - 1];
    }
    long long int p = 0;
    for (int i = (n - 1); i >= (0); i--) {
      ans += ((pre[m - p - 1] * (a[i] - '0') * powmod(2, p))) % mod;
      ans %= mod;
      p++;
      if (p > m - 1) break;
    }
    cout << ans << "\n";
  }
  return 0;
}
