#include <bits/stdc++.h>
using namespace std;
long long pow1(long long power, long long num) {
  if (num == 0) return 1;
  return power * pow1(power, num - 1) % 998244353;
}
void solve() {
  int w, h;
  cin >> w >> h;
  cout << ((long long)(4 * (long long)pow1(2, w - 1) *
                       (long long)pow1(2, h - 1))) %
              998244353
       << "\n";
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int t = 1;
  for (int i = 1; i <= t; i++) {
    solve();
  }
}
