MOD = 998244353

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

k_max = min(N + 1, M + 1)

# Precompute binomial coefficients up to k_max
comb = [[0] * (k_max + 2) for _ in range(k_max + 2)]
comb[0][0] = 1
for k in range(1, k_max + 1):
    comb[k][0] = 1
    comb[k][k] = 1
    for s in range(1, k):
        comb[k][s] = (comb[k-1][s-1] + comb[k-1][s]) % MOD

total = 0
for k in range(1, k_max + 1):
    if (k - 1) > M:
        continue
    sum_s = 0
    for s in range(0, k + 1):
        sign = (-1) ** s
        c = comb[k][s]
        term = (2 * M + 1 - s) % MOD
        term_pow = pow(term, N, MOD)
        contribution = sign * c * term_pow
        sum_s = (sum_s + contribution) % MOD
    sum_s = sum_s % MOD
    total = (total + k * sum_s) % MOD

print(total % MOD)