#include <bits/stdc++.h>
using namespace std;
unsigned long long ull_pow(unsigned long long base, unsigned long long k) {
  unsigned long long r = 1;
  base %= 998244353;
  while (k > 0) {
    if (k & 1) r = (r * base) % 998244353;
    k = k >> 1;
    base = (base * base) % 998244353;
  }
  return r;
}
int main() {
  unsigned long long w, h, ans, tmp;
  cin >> w >> h;
  tmp = (w % 998244353 + h % 998244353) % 998244353;
  ans = ull_pow(2, tmp) % 998244353;
  cout << ans << endl;
}
