#include <bits/stdc++.h>
using namespace std;
static long long l = 998244353;
int main() {
  int w, h;
  cin >> w;
  cin >> h;
  int total = w + h;
  long long res = 1;
  while (total--) {
    res = ((res % l) * 2) % l;
  }
  cout << res;
}
