MOD = 998244353

N, M = map(int, input().split())

total = M + 2 * N
k = 2 * N + 1

if total >= MOD:
    print(0)
else:
    if k > total:
        print(0)
    else:
        res = 1
        for i in range(1, k + 1):
            numerator = (total - k + i) % MOD
            res = res * numerator % MOD
            inv_i = pow(i, MOD - 2, MOD)
            res = res * inv_i % MOD
        ans = res * N % MOD
        print(ans)