#include <bits/stdc++.h>
using namespace std;
int main() {
  int w, c, x = 1;
  int m = 998244353;
  cin >> w >> c;
  while (w--) {
    x = (2 * x) % m;
  }
  while (c--) {
    x = (2 * x) % m;
  }
  cout << x << endl;
}
