#include<bits/stdc++.h>
using namespace std;
#include <unordered_set>
#include <random>
#define int long long
#define REP(i,m,n) for(int i=(m);i<(n);i++)
#define rep(i,n) REP(i,0,n)
#define pb push_back
#define all(a) a.begin(),a.end()
#define rall(c) (c).rbegin(),(c).rend()
#define mp make_pair
#define endl '\n'
//#define vec vector<ll>
//#define mat vector<vector<ll> >
#define fi first
#define se second
#define double long double
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll,ll> pll;
//typedef long double ld;
typedef complex<double> Complex;
const ll INF=1e9+7;
const ll MOD=998244353;
const ll inf=INF*INF;
const ll mod=MOD;
const ll MAX=200010;
const double PI=acos(-1.0);
typedef vector<vector<ll> > mat;
typedef vector<ll> vec;

//二分累乗

ll rui(ll a,ll b){
    ll res=1;
    ll x=a;
    while(b){
        if(b&1)res=res*x%mod;
        x=x*x%mod;
        b/=2;
    }
    return res;
}

void solve(){
    ll n,m;cin>>n>>m;
    vector<vector<ll> >dp(n+1,vector<ll>(m+1));
    vector<ll>sum(n+1);
    sum[0]=1;
    dp[0][0]=1;
    ll ans=0;
    REP(i,1,n+1){
        vector<ll>just(m+1);
        REP(j,1,m+1){
            if(i>=j){
                just[j]=(sum[i-j]-dp[i-j][j])%mod;
            }else{
                break;
            }
        }
        REP(j,1,m+1){
            dp[i][j]=(sum[i-1]-just[j])%mod;
        }
        REP(j,1,m+1){
            sum[i]=(sum[i]+dp[i][j])%mod;
        }
        ll x=rui(m,n-i);
        REP(j,1,m+1){
            ans=(ans+x*just[j]%mod)%mod;
        }
    }
    if(ans<0)ans+=mod;
    cout<<ans<<endl;
}

signed main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    solve();
}