#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

#include <atcoder/modint>
using mint = atcoder::modint998244353;

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  ll h, w;
  cin >> h >> w;
  cout << mint(2).pow((h - 1) * (w - 1) + 2).val() << '\n';
  return 0;
}