#include <bits/stdc++.h>
using namespace std;
string digit = "0123456789";
string small = "abcdefghijklmnopqrstuvwxyz";
string capital = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
int dx8[] = {0, 0, 1, 1, 1, -1, -1, -1};
int dy8[] = {1, -1, 1, -1, 0, 0, -1, 1};
int dx4[] = {1, -1, 0, 0};
int dy4[] = {0, 0, 1, -1};
int mod = 998244353;
int main() {
  int w, d;
  cin >> w >> d;
  int tot = w + d;
  long long ans = 1;
  for (int i = 1; i <= tot; i++) {
    ans = (2 * ans);
    ans %= mod;
  }
  cout << ans << "\n";
}
