#include <bits/stdc++.h>
using namespace std;

using ll = long long;
constexpr int mod = 998244353;

ll mpow(ll a, ll b) {
	ll p = a, r = 1;
	for(int i = 0; i < 60; ++i) {
		if(b >> i & 1) r = (r * p) % mod;
		p = (p * p) % mod;
	}
	return r;
}

int main(void) {
	ll H, W;
	cin >> H >> W;
	
	cout << mpow(2, (H - 1) * (W - 1) + 2) << "\n";
	
	return 0;
}