def main():
    MOD = 998244353

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

    f = [0] * (N+1)
    for mex in range(1, min(N, M+1)+1):
        DP = [1] + [0] * mex
        for i in range(1, N+1):
            for j in range(mex, -1, -1):
                DP[j] = (((M+1)-(mex-j)) * DP[j] + (mex-(j-1))
                         * (DP[j-1] if j != 0 else 0)) % MOD
            f[i] = (f[i] + DP[-1]) % MOD

    ans = 0
    C = 1
    for i in range(1, N+1):
        C = C * (N-i+1) * pow(i, -1, MOD) % MOD
        ans = (ans + pow(M+1, N-i, MOD) * C * f[i]) % MOD

    print(ans)


if __name__ == '__main__':
    main()