#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define int long long
typedef pair<int, int> P;
const int MAX_N = 1e5 + 5;
const ll mod = 998244353;

int qpow(int a, int b)
{
    int ans = 1;
    while (b)
    {
        if (b & 1)
            ans = ans * a % mod;
        b >>= 1;
        a = a * a % mod;
    }
    return ans;
}

void solve()
{
    int n, m;
    cin >> n >> m;
    int ans = qpow(m, n) * (2 * m + 1) % mod;
    int sum = 0;
    for (int i = 1; i <= m; i++)
    {
        sum += qpow(i, n) % mod;
    }
    cout << (ans - 2 * sum % mod + mod) % mod << '\n';
}
signed main()
{
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);

    int t = 1;
    // cin>>t;
    while (t--)
    {
        solve();
    }
    return 0;
}