#include <bits/stdc++.h>
using namespace std;
void fastIO() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.precision(20);
}
long long A[300006];
long long B[300006];
long long C[300006];
int main() {
  fastIO();
  long long a, b, c, n, m, k, p, q, r;
  long long cnt = 0, cntr = 0, sum = 0, ans = 1, check = 0;
  float x, y, z;
  long long Max = -1e18;
  unsigned long long Min = 1e20;
  string s, s1, s3, s4;
  long long height, width;
  long long rem = (long long)998244353;
  cin >> width >> height;
  m = width;
  n = height;
  for (int i = 1; i <= n + m; i++) {
    ans = (ans * 2) % rem;
  }
  cout << ans << endl;
  return 0;
}
