MOD = 998244353

a, b = map(int, input().split())
N = a + b + 10

fac = [-1 for _ in range(N + 1)]
fac[0] = 1
for i in range(1, N + 1):
    fac[i] = (fac[i - 1] * i) % MOD

inv_fac = [-1 for _ in range(N + 1)]
inv_fac[N] = pow(fac[N], MOD - 2, MOD)
for i in reversed(range(1, N + 1)):
    inv_fac[i - 1] = (i * inv_fac[i]) % MOD

def P(n, r, MOD):
    return (fac[n] * inv_fac[n - r]) % MOD

def C(n, r, MOD):
    return (fac[n] * inv_fac[n - r] * inv_fac[r]) % MOD

print(C(a + b - 2, a - 1, MOD))