#include <bits/stdc++.h>
using namespace std;
long long int power(long long int a, long long int b) {
  if (b == 0) return 1;
  if (b == 1) return a;
  if (b % 2 == 1) return (power(a, b - 1) * a) % 998244353;
  long long int q = power(a, b / 2);
  return (q * q) % 998244353;
}
long long binpow(long long a, long long b, long long m) {
  a %= m;
  long long res = 1;
  while (b > 0) {
    if (b & 1) res = res * a % m;
    a = a * a % m;
    b >>= 1;
  }
  return res;
}
void solve() {
  long long int n, m;
  cin >> n >> m;
  string A, B;
  cin >> A >> B;
  reverse(A.begin(), A.end());
  reverse(B.begin(), B.end());
  long long int ans = 0;
  vector<long long int> pre(2e5 + 10, 0);
  vector<long long int> preadd(2e5 + 10, 0);
  for (long long int i = 0; i < (n); ++i) {
    if (A[i] == '1') {
      preadd[i] = 1;
      pre[i] = 1;
    }
  }
  for (long long int i = 0; i < (2e5 + 10); ++i) {
    if (preadd[i] == 1) preadd[i] = binpow(2, i, 998244353);
  }
  for (long long int i = 0; i < (2e5 + 10); ++i) {
    if (i != 0) {
      preadd[i] = (preadd[i - 1] + preadd[i]) % 998244353;
      pre[i] += pre[i - 1];
    }
  }
  for (long long int i = 0; i < (m); ++i) {
    if (B[i] == '1') {
      ans = (ans + preadd[i]) % 998244353;
    }
  }
  cout << ans << "\n";
}
int main() {
  ios_base::sync_with_stdio(false), cin.tie(NULL), cout.tie(NULL);
  int T = 1;
  while (T--) {
    solve();
  }
  return 0;
}
