#include <bits/stdc++.h>
using namespace std;
using ll = long long;
ll power(ll x, ll y);
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ll t;
  t = 1;
  while (t--) {
    ll n, m;
    cin >> n >> m;
    cout << power(2, n + m);
  }
}
ll power(ll x, ll y) {
  ll res = 1;
  x %= 998244353;
  while (y > 0) {
    if (y & 1) res = (res * x) % 998244353;
    y = y >> 1, x = (x * x) % 998244353;
  }
  return res;
}
