#include <bits/stdc++.h>
using namespace std;
const long long mod = 998244353;
long long n, m, ans = 1;
long long Read() {
  long long k = 0, tmp = 1;
  char _c = getchar();
  while (_c > '9' or _c < '0') {
    if (_c == '-') tmp = -1;
    _c = getchar();
  }
  while (_c <= '9' and _c >= '0') {
    k = (k << 1) + (k << 3) + (_c ^ 48);
    _c = getchar();
  }
  return k * tmp;
}
void Work();
int main() { Work(); }
void Work() {
  n = Read(), m = Read();
  for (int i = 1; i <= n + m; i++) {
    ans = ans * 2 % mod;
  }
  cout << ans;
}
