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

C = 10 ** 5 * 2 + 4
fact = [1] * C
P = 998244353
for i in range(2,C):
    fact[i] = fact[i-1] * i % P
def inv(k):
    return pow(k,P-2,P)
ans = fact[a + b - 2] * inc(fact[a - 1]) % P * inv(fact[b - 1]) % P
print(ans)