import sys

input = sys.stdin.buffer.readline

n, m = map(int, input().split())
mod = 998244353
bunbo = 1
bunshi = 1
nn = n % mod
mm = m % mod
# ans = n * binom(2 * n + m, 2 * n + 1)
for i in range(2 * n + 1):
    bunbo *= (2 * nn + mm - i) % mod
    bunbo %= mod
    bunshi *= 1 + i
    bunshi %= mod
ans = bunbo * pow(bunshi, mod - 2, mod) % mod * n % mod
print(ans)