#include <bits/stdc++.h>
using namespace std;
const int mod = 998244353;
int main() {
  int w, h;
  cin >> w >> h;
  int ans = 1;
  for (int i = 1; i <= w + h; i++) {
    ans = (ans * 2) % mod;
  }
  cout << ans << endl;
}
