def main():
    MOD = 998244353

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

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

    ans = 0

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

    print(ans)


if __name__ == '__main__':
    main()