#include <bits/stdc++.h>
using namespace std;
#include <atcoder/modint>
using namespace atcoder;
using mint = modint998244353;
//using mint = modint1000000007;
using ll = long long;
using ld = long double;
using pll = pair<ll, ll>;
using tlll = tuple<ll, ll, ll>;
constexpr ll INF = 1LL << 60;
template<class T> bool chmin(T& a, T b) {if (a > b) {a = b; return true;} return false;}
template<class T> bool chmax(T& a, T b) {if (a < b) {a = b; return true;} return false;}
ll safemod(ll A, ll M) {return (A % M + M) % M;}
ll divfloor(ll A, ll B) {if (B < 0) {return divfloor(-A, -B);} return (A - safemod(A, B)) / B;}
ll divceil(ll A, ll B) {if (B < 0) {return divceil(-A, -B);} return divfloor(A + B - 1, B);}
#define FINALANS(A) do {cout << (A) << '\n'; exit(0);} while (false)

mint sum0(mint a, ll n) // sum[i = 0 to n - 1] a^i
{
  return (1 - a.pow(n)) / (1 - a);
}

mint sum1(mint a, ll n) // sum[i = 0 to n - 1] ia^i
{
  return (sum0(a, n) - 1 - (n - 1) * a.pow(n)) / (1 - a);
}

int main()
{
  ll N, K;
  cin >> N >> K;

  mint ans = 0;
  for (ll x = 1; x <= K; x++)
  {
    /*
    mint tmp0 = 0, tmp1 = 0;
    for (ll i = 0; i < N - 1; i++)
    {
      tmp0 += (N * (K - x) + 1) * mint(x - 1).pow(i) * mint(x).pow(N - i - 2);
      tmp1 += i * mint(x - 1).pow(i) * mint(x).pow(N - i - 2);
    }
    mint tmp = tmp0 + tmp1;
    ans += x * tmp;

    cerr << x << " " << tmp0.val() << " " << tmp1.val() << " " << tmp.val() << endl;
    //*/

    //*
    mint y = mint(x - 1) / mint(x);
    mint tmp0 = (N * (K - x) + 1) * mint(x).pow(N - 2) * sum0(y, N - 1);
    mint tmp1 = mint(x).pow(N - 2) * sum1(y, N - 1);
    mint tmp = tmp0 + tmp1;
    ans += x * tmp;
    //*/

    //cerr << x << " " << tmp0.val() << " " << tmp1.val() << " " << tmp.val() << endl;
  }
  cout << ans.val() << endl;
}