#include <bits/stdc++.h>

using namespace std;

#define F(i, a, b) for (int i = a; i < b; i++)
#define ALL(x) x.begin(), x.end()
#define IOS ios_base::sync_with_stdio(0)

typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef long long ll;

#define MOD 998244353ll

ll fastPow(ll a, ll b) {
  ll ans = 1;
  while (b) {
    if (b & 1) {
      ans = (ans * a) % MOD;
    }
    a = (a * a) % MOD;
    b >>= 1;
  }

  return ans;
}

int main() {
  ll n, m;
  cin >> n >> m;
  ll ans = 0;
  for (ll y = 1; y < m; y++) {
    ans = (ans + 2 * (fastPow(m, n) - fastPow(y, n))) % MOD;
    ans = (ans + MOD) % MOD;
  }
  ans = (ans + fastPow(m, n)) % MOD;

  cout << ans << '\n';
}