A, B = map(int, input().split())
# comb(A+B-2, A-1)
MOD = 998244353
modinv = lambda x, mod=MOD: pow(x, mod - 2, mod)
ans = 1
for i in range(A - 1):
    ans *= (A + B - 2 - i) * modinv(i + 1)
    ans %= MOD
print(ans)