MOD = 998244353

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

m = M % MOD

# Compute numerator: product of (m + 2N - i) for i in 0..2N-1
numerator = 1
for i in range(2 * N):
    term = (m + 2 * N - i) % MOD
    numerator = numerator * term % MOD

# Compute denominator: (2N)! mod MOD
denominator = 1
for i in range(1, 2 * N + 1):
    denominator = denominator * i % MOD

# Compute inverse of denominator
inv_denominator = pow(denominator, MOD - 2, MOD)

# Compute combination: C(M + 2N, 2N) mod MOD
comb = numerator * inv_denominator % MOD

# Compute a = (M * N) mod MOD
a = (m * N) % MOD

# Compute inverse of (2N + 1)
inv_2n_plus_1 = pow(2 * N + 1, MOD - 2, MOD)

# Final answer calculation
ans = a * comb % MOD
ans = ans * inv_2n_plus_1 % MOD

print(ans)