## https://yukicoder.me/problems/no/1897

MOD = 998244353

def my_pow(k, n):
    if k > 0:
        return pow(k, n, MOD)
    else:
        return 0

def main():
    N, K = map(int, input().split())

    answer = 0
    for k in reversed(range(1, K + 1)):
        # 一番大きい値がkの場合
        ans1 = my_pow(k, N)
        ans1 -= my_pow(k - 1, N)
        ans1 %= MOD
        ans1 -= (N * my_pow(k - 1, N - 1)) % MOD
        ans1 %= MOD

        # 一番大きい値がkより大きい場合
        ans2 = my_pow(k, N - 1)
        ans2 -= my_pow(k - 1, N - 1)
        ans2 %= MOD
        ans2 *= (K - k)
        ans2 %= MOD
        ans2 *= N
        ans2 %= MOD
#        print(f"k = {k}, ans1 = {ans1}, ans2 = {ans2}")

        ans = (ans1 + ans2) % MOD
        answer += (ans * k) % MOD
        answer %= MOD
    print(answer)








if __name__ == "__main__":
    main()