MOD = 998244353

def main():
    import sys
    N, M = map(int, sys.stdin.readline().split())
    max_x = min(N + 1, M + 1)
    
    # Precompute combinations C[x][s]
    C = [[0] * (2001) for _ in range(2001)]
    C[0][0] = 1
    for x in range(1, 2001):
        C[x][0] = 1
        for s in range(1, x+1):
            C[x][s] = (C[x-1][s-1] + C[x-1][s]) % MOD
    
    ans = 0
    for x in range(1, max_x + 1):
        if x - 1 > M:
            continue
        res = 0
        for s in range(0, x+1):
            sign = (-1) ** (x - s)
            comb = C[x][s]
            if x <= M:
                base = (s + 2 * M - x + 1) % MOD
            else:
                base = (s + x + 1) % MOD
            # Compute base^N mod MOD
            pow_val = pow(base, N, MOD)
            term = comb * pow_val
            term %= MOD
            if (x - s) % 2 == 1:
                term = (-term) % MOD
            res = (res + term) % MOD
        ans = (ans + x * res) % MOD
    print(ans % MOD)

if __name__ == "__main__":
    main()