#include <bits/stdc++.h>
using namespace std;
constexpr int MOD = 998244353;
constexpr int MAXN = 2e6 + 10;
using ll = long long;
using Pii = pair<int, int>;
using Pll = pair<ll, ll>;
ll N, M, K, T;
ll FastPow(ll x, ll exp) {
  ll ret = 1;
  while (exp) {
    if (exp & 1) {
      ret = ret * x % MOD;
    }
    x = x * x % MOD;
    exp >>= 1;
  }
  return ret;
}
ll Solution() { return FastPow(2, N + M); }
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr), cout.tie(nullptr);
  while (cin >> N >> M) {
    cout << Solution() << '\n';
  }
  return 0;
}
