#include <bits/stdc++.h>
using namespace std;
vector<string> split(const string& input) {
  istringstream buffer(input);
  vector<string> ret;
  copy(istream_iterator<string>(buffer), istream_iterator<string>(),
       back_inserter(ret));
  return ret;
}
int T = 1;
int R, C;
int N, M, K;
string S;
int dr[] = {-1, 0, 1, 0, 1, -1, 1, -1};
int dc[] = {0, 1, 0, -1, -1, 1, 1, -1};
char DIRS[] = {'N', 'E', 'S', 'W'};
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  cin >> N >> M;
  int ans = 1;
  for (int i = int(1); i <= int(N + M); i++) {
    ans = (ans * 2) % 998244353;
  }
  cout << ans << endl;
  return 0;
}
