MOD = 998244353
N = 200000
fact = [0 for _ in range(N)]
invfact = [0 for _ in range(N)]
fact[0] = 1
for i in range(1, N):
    fact[i] = fact[i - 1] * i % MOD

invfact[N - 1] = pow(fact[N - 1], MOD - 2, MOD)

for i in range(N - 2, -1, -1):
    invfact[i] = invfact[i + 1] * (i + 1) % MOD

def nCk(n, k):
    if k < 0 or n < k:
        return 0
    else:
        return (fact[n] * invfact[k] % MOD) * invfact[n - k] % MOD

def nPk(n, k):
    if k < 0 or n < k:
        return 0
    else:
        return fact[n] * invfact[n - k] % MOD

def nHk(n, k):
    if n == k == 0:
        return 1
    return nCk(n + k - 1, k)

x, y = map(int, input().split())
if y >= 5000:
    exit()

bi = [1]
for _ in range(min(x, y) + 1):
    bi.append(bi[-1] * 2 % MOD)

ans = 0
for i in range(min(x, y) + 1):
    xx = x - i
    yy = y - i
    for cc in range(i + 1):
        tot = bi[cc]
        times = nCk(xx + yy + cc, cc) * nCk(xx + yy, xx) % MOD
        ans += tot * times % MOD
        ans %= MOD

print(ans)