#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#define _GLIBCXX_DEBUG
using namespace std;
using std::cout;
using std::cin;
using std::endl;
using ll=long long;
using ld=long double;
ll ILL=1167167167167167167;
const int INF=2100000000;
const ll mod=998244353;
#define rep(i,a) for (ll i=0;i<a;i++)
#define all(p) p.begin(),p.end()
template<class T> using _pq = priority_queue<T, vector<T>, greater<T>>;
template<class T> ll LB(vector<T> &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> ll UB(vector<T> &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> bool chmin(T &a,const T &b){if(a>b){a=b;return 1;}else return 0;}
template<class T> bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}else return 0;}
template<class T> void So(vector<T> &v) {sort(v.begin(),v.end());}
template<class T> void Sore(vector<T> &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});}
void yneos(bool a){if(a) cout<<"Yes\n"; else cout<<"No\n";}
template<class T> void vec_out(vector<T> &p){for(int i=0;i<(int)(p.size());i++){if(i) cout<<" ";cout<<p[i];}cout<<"\n";}




void solve();
// oddloop
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	
	int t=1;
	//cin>>t;
	rep(i,t) solve();
}

void solve(){
	ll N,M;
	cin>>N>>M;
	vector<ll> sum(N+2);
	vector<vector<ll>> seg(M);
	rep(i,M){
		seg[i].resize(N+2,0);
	}
	sum[0]=1;
	sum[1]=-1;
	ll X=1;
	rep(i,N){
		X=(X*M)%mod;
		sum[i]%=mod;
		rep(j,M){
			seg[j][i]%=mod;
			ll tmp=sum[i]-seg[j][i];
			seg[j][i+1]+=tmp;
			sum[i+1]+=tmp;
			ll x=(i+j+1);
			chmin(x,N+1);
			seg[j][x]-=tmp;
			sum[x]-=tmp;
			seg[j][i+1]+=seg[j][i];
		}
		sum[i+1]+=sum[i];
	}
	/*rep(i,N){
		cout<<sum[i]<<"\n";
		rep(j,M) cout<<seg[j][i]<<" ";
		cout<<"\n";
	}*/
	//cout<<X<<" "<<sum[N]<<"\n";
	cout<<((X-sum[N])%mod+mod)%mod<<"\n";
}