#include <bits/stdc++.h>
using namespace std;
const double PI = 3.1415926535897932384626433832795;
const long long INF = 1LL << 62;
const long long MINF = -1LL << 62;
template <typename T>
T getint() {
  T val = 0;
  char c;
  bool neg = false;
  while ((c = getchar()) && !(c >= '0' && c <= '9')) {
    neg |= c == '-';
  }
  do {
    val = (val * 10) + c - '0';
  } while ((c = getchar()) && (c >= '0' && c <= '9'));
  return val * (neg ? -1 : 1);
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int a, b;
  cin >> a >> b;
  long long res = 1;
  long long mod = 998244353;
  for (int i = 0; i < a + b; ++i) res = res * 2 % mod;
  cout << res << "\n";
  return 0;
}
