#include <bits/stdc++.h>
using namespace std;
long long int mod = 998244353;
long long int power(long long int a, long long int b, long long int mod) {
  long long int res = 1;
  while (b) {
    if (b % 2 == 1) res = ((res % mod) * (a % mod)) % mod;
    a = ((a % mod) * (a % mod)) % mod;
    b = b / 2;
  }
  return res;
}
signed main() {
  long long int Q = 1;
  while (Q--) {
    long long int a, b;
    cin >> a >> b;
    cout << power(2, (a + b), mod) << endl;
  }
}
