#include <bits/stdc++.h>
using namespace std;
const int P = 998244353;
int x, y;
int ksm(int a, int b) {
  int ans = 1;
  for (; b; b >>= 1, a = 1ll * a * a % P)
    if (b & 1) ans = 1ll * ans * a % P;
  return ans;
}
int main() {
  scanf("%d%d", &x, &y);
  printf("%d\n", ksm(2, x + y));
  return 0;
}
