a, b = map(int, input().split())
mod = 998244353

fact = [1] * (a + b)
inv = [1] * (a + b)
finv = [1] * (a + b)
for i in range(2, a + b):
    fact[i] = fact[i - 1] * i % mod
    inv[i] = mod - inv[mod % i] * (mod // i) % mod
    finv[i] = finv[i - 1] * inv[i] % mod
def comb(x, y):
    return fact[x] * finv[y] % mod * finv[x - y] % mod

print(comb(a + b - 2, a - 1))