#include #include using namespace std; using isize = size_t; using i32 = int; using u32 = unsigned int; using i64 = long long; using u64 = unsigned long long; using i128 = __int128_t; using u128 = __uint128_t; using f64 = long double; using p2 = pair; using el = tuple; using mint = atcoder::modint998244353; void _main(); int main() { cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(18); _main(); } i64 pow(i64 x, i64 n) { i64 res = 1; i64 t = x; while (n > 0) { if (n & 1) res *= t; t *= t; n >>= 1; } return res; } void _main() { i64 h, w; cin >> h >> w; mint s = 8; for (i64 i = 2; i < h; i++) s *= 2; mint k = mint(2).pow(h - 1); for (i64 j = 2; j < w; j++) s *= k; cout << s.val() << "\n"; }