mod = 998244353
n = 100010
fac = [0] * (n + 1)
invf = [0] * (n + 1)
inv = [0] * (n + 1)
fac[0] = 1
fac[1] = 1
invf[0] = 1
invf[1] = 1
inv[1] = 1	
for i in range(2, n + 1):
	fac[i] = fac[i - 1] * i % mod
	inv[i] = mod - inv[mod % i] * (mod // i) % mod
	invf[i] = invf[i - 1] * inv[i] % mod
def C(a, b):
	return invf[b] * invf[a - b] * fac[a] % mod
H, W = map(int, input().split())
if H == 1 or W == 1:
	exit(print(1))
mod = 998244353
ans = 0
for i in range(H + W - 2):
	x = i // 2
	y = i // 2 + i % 2
	if x <= H - 2 and y <= W - 1:
		ans += pow(2, (H - 1) * (W - 1) - i, mod) * C(H - 2, x) * C(W - 1, y) % mod
print(ans % mod)