mod = 998244353
n = 505050
fact = [1] * (n + 1)
invfact = [1] * (n + 1)
for i in range(1, n):
    fact[i + 1] = ((i+1) * fact[i]) % mod
invfact[n] = pow(fact[n], mod - 2, mod)
for i in range(n - 1, -1, -1):
    invfact[i] = invfact[i + 1] * (i + 1) % mod

def comb(n, r):
    if n < 0 or r < 0 or n - r < 0:
        return 0
    return fact[n] * invfact[r] * invfact[n - r] % mod

H, W = map(int, input().split())
ans = 0
for k1 in range(H + 1):
    for k2 in range(W + 1):
        ans += comb(k1, H - k1) * comb(k2, W - k2) * comb(k1 + k2, k1)
        ans %= mod
        
print(ans)