#include <bits/stdc++.h>
using namespace std;
const int MOD = 998244353;
long long BigMod(long long b, long long a) {
  if (a == 0) {
    return 1;
  }
  long long x = BigMod(b, a / 2);
  x = (x * x) % MOD;
  if (a % 2) x = (x * b) % MOD;
  return x;
}
int main() {
  long long a, b;
  cin >> a >> b;
  cout << BigMod(2, a + b) << endl;
}
