//Let's join Kaede Takagaki Fan Club !!
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <ctime>
#include <cassert>
#include <string>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <functional>
#include <iostream>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <cassert>
#include <iomanip>
#include <chrono>
#include <random>
#include <bitset>
#include <complex>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
#define int long long
//#define L __int128
typedef long long ll;
typedef pair<int,int> P;
typedef pair<int,P> P1;
typedef pair<P,P> P2;
#define pu push
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define eps 1e-7
#define INF 1000000000
#define a first
#define b second
#define fi first
#define sc second
//#define rng(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define rep(i,x) for(int i=0;i<x;i++)
#define repn(i,x) for(int i=1;i<=x;i++)
#define SORT(x) sort(x.begin(),x.end())
#define ERASE(x) x.erase(unique(x.begin(),x.end()),x.end())
#define POSL(x,v) (lower_bound(x.begin(),x.end(),v)-x.begin())
#define POSU(x,v) (upper_bound(x.begin(),x.end(),v)-x.begin())
#define all(x) x.begin(),x.end()
#define si(x) int(x.size())
#define pcnt(x) __builtin_popcountll(x)

#ifdef LOCAL
#define dmp(x) cerr<<__LINE__<<" "<<#x<<" "<<x<<endl
#else
#define dmp(x) void(0)
#endif
 
template<class t,class u> bool chmax(t&a,u b){if(a<b){a=b;return true;}else return false;}
template<class t,class u> bool chmin(t&a,u b){if(b<a){a=b;return true;}else return false;}
 
template<class t> using vc=vector<t>;
 
template<class t,class u>
ostream& operator<<(ostream& os,const pair<t,u>& p){
	return os<<"{"<<p.fi<<","<<p.sc<<"}";
}
 
template<class t> ostream& operator<<(ostream& os,const vc<t>& v){
	os<<"{";
	for(auto e:v)os<<e<<",";
	return os<<"}";
}
 
 //https://codeforces.com/blog/entry/62393
struct custom_hash {
	static uint64_t splitmix64(uint64_t x) {
		// http://xorshift.di.unimi.it/splitmix64.c
		x += 0x9e3779b97f4a7c15;
		x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
		x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
		return x ^ (x >> 31);
	}
 
	size_t operator()(uint64_t x) const {
		static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
		return splitmix64(x + FIXED_RANDOM);
	}
	//don't make x negative!
	size_t operator()(pair<int,int> x)const{
		return operator()(uint64_t(x.first)<<32|x.second);
	}
};
//unordered_set -> dtype, null_type
//unordered_map -> dtype(key), dtype(value)
using namespace __gnu_pbds;
template<class t,class u>
using hash_table=gp_hash_table<t,u,custom_hash>;

template<class T>
void g(T &a){
	cin >> a;
}
template<class T>
void o(const T &a,bool space=false){
	cout << a << (space?' ':'\n');
}
//ios::sync_with_stdio(false);
const ll mod = 998244353;
//const ll mod = 1000000007;
mt19937_64 mt(chrono::steady_clock::now().time_since_epoch().count());
template<class T>
void add(T&a,T b){
	a+=b;
	if(a >= mod) a-=mod;
}
ll modpow(ll x,ll n){
	ll res=1;
	while(n>0){
		if(n&1) res=res*x%mod;
		x=x*x%mod;
		n>>=1;
	}
	return res;
}
#define _sz 400005
ll F[_sz],R[_sz];
void make(){
	F[0] = 1;
	for(int i=1;i<_sz;i++) F[i] = F[i-1]*i%mod;
	R[_sz-1] = modpow(F[_sz-1], mod-2);
	for(int i=_sz-2;i>=0;i--) R[i] = R[i+1] * (i+1) % mod;
}
ll C(int a,int b){
	if(b < 0 || a < b) return 0;
	return F[a]*R[b]%mod*R[a-b]%mod;
}
template<const int md>
struct ntt{
	inline void add(int &a, int b) { a += b; if(a >= md) a -= md; }
	inline void sub(int &a, int b) { a -= b; if(a < 0) a += md; }
	inline int mul(int a, int b) { return (int)((ll)a*b%md); }
	inline int power(int a, long long b) {
		int res = 1;
		while (b > 0) {
			if (b & 1) res = mul(res, a);
			a = mul(a, a);
			b >>= 1;
		}
		return res;
	}
	inline int inv(int a) {
		a %= md;
		if (a < 0) a += md;
		int b = md, u = 0, v = 1;
		while (a) {
			int t = b / a;
			b -= t * a; swap(a, b);
			u -= t * v; swap(u, v);
		}
		assert(b == 1);
		if (u < 0) u += md;
		return u;
	}
	
	int max_base, root;
	vector<int> dw, idw;
	ntt() {
		int tmp = md - 1;
		max_base = 0;
		while (tmp % 2 == 0) {
			tmp /= 2;
			max_base++;
		}
		root = 2;
		while (power(root, (md-1)>>1) == 1) root++;
		dw.resize(max_base); idw.resize(max_base);
		rep(i, max_base){
			sub(dw[i], power(root, (md-1) >> (i+2)));
			idw[i] = inv(dw[i]);
		}
	}
	void fft(vector<int> &a, bool inv) {
		const int n = a.size();
		assert((n & (n - 1)) == 0);
		assert(__builtin_ctz(n) <= max_base);
		if(!inv){
			for(int m=n;m>>=1;){
				int w = 1;
				for(int s=0,k=0; s<n; s += 2*m){
					for(int i=s, j=s+m ; i < s+m; ++i, ++j) {
						int x = a[i], y = mul(a[j], w);
						a[j] = (x>=y?x-y:x+md-y);
						a[i] = (x+y>=md?x+y-md:x+y);
					}
					w = mul(w, dw[__builtin_ctz(++k)]);
				}
			}
		}
		else{
			for(int m=1;m<n;m*=2){
				int w = 1;
				for(int s=0,k=0; s<n; s += 2*m){
					for(int i=s, j=s+m ; i < s+m; ++i, ++j) {
						int x = a[i], y = a[j];
						a[j] = (x>=y?x-y:x+md-y);
						a[j] = mul(a[j], w);
						a[i] = (x+y>=md?x+y-md:x+y);
					}
					w = mul(w, idw[__builtin_ctz(++k)]);
				}
			}
			const int inv_sz = this->inv(n);
			for(auto &&e:a) e = mul(e, inv_sz);
		}
	}
	vector<int> multiply(vector<int> a, vector<int> b, int eq = 0) {
		int need = a.size() + b.size() - 1;
		int nbase = 0;
		while ((1 << nbase) < need) nbase++;
		int sz = 1 << nbase;
		a.resize(sz);
		b.resize(sz);
		fft(a, 0);
		if (eq) b = a; else fft(b, 0);
		rep(i, sz) a[i] = mul(a[i], b[i]);
		fft(a, 1);
		a.resize(need);
		return a;
	}
	vector<int> square(vector<int> a) {
		return multiply(a, a, 1);
	}
};
ntt<998244353>nt;

#define vi vector<int>
vi init(vi a, int x){
	a.resize(x,0);
	return a;
}
vi add(vi a, vi b,int M=-1){
	if(a.size() < b.size()) swap(a,b);
	for(int i=0;i<b.size();i++){
		a[i]+=b[i];
		if(a[i] < 0) a[i] += mod;
		if(a[i] >= mod) a[i] -= mod;
	}
	if(M >= 0 && a.size() > M) a.resize(M);
	return a;
}
vi sub(vi a, vi b,int M=-1){
	if(a.size() < b.size()) a.resize(b.size(),0);
	for(int i=0;i<b.size();i++){
		a[i]-=b[i];
		if(a[i] < 0) a[i] += mod;
		if(a[i] >= mod) a[i] -= mod;
	}
	if(M >= 0 && a.size() > M) a.resize(M);
	return a;
}
//微分
vi diff(vi a,int M=-1){
	reverse(a.begin(),a.end());
	a.pop_back();
	reverse(a.begin(),a.end());
	for(int i=0;i<a.size();i++) a[i] = 1LL*a[i]*(i+1)%mod;
	if(M >= 0 && a.size() > M) a.resize(M);
	if(a.empty()) a.pb(0);
	return a;
}
//積分、定数項は指定可能
vi intg(vi a,int coef=0,int M=-1){
	reverse(a.begin(),a.end());
	a.push_back(coef);
	reverse(a.begin(),a.end());
	for(int i=1;i<a.size();i++) a[i] = 1LL*a[i]*modpow(i,mod-2)%mod;
	if(M >= 0 && a.size() > M) a.resize(M);
	return a;
}
vi mul_int(vi a,int x,int M=-1){
	for(int i=0;i<a.size();i++){
		ll A = 1LL*a[i]*x%mod;
		if(A < 0) A += mod;
		a[i] = A;
	}
	if(M >= 0 && a.size() > M) a.resize(M);
	return a;
}
vi mul(vi a,vi b,int M=-1){
	//modが99...のときはnttできる
	//任意modの場合は、適当に区切ってもいいしgarnerしてもいいし任せます
	a = nt.multiply(a,b);
	if(M >= 0 && a.size() > M) a.resize(M);
	return a;
}
vi lw(vi a, int x){
	if(a.size() > x) a.resize(x);
	return a;
}
vi inv(vi a,int M){
	if(a.empty() || a[0] == 0) return vi();
	//1の場合をやっておく
	vi ret(1);
	ret[0] = modpow(a[0],mod-2);
	int cur = 1;
	int nxt = 1;
	while(cur < M){
		auto g = lw(ret, cur);
		auto f = lw(a, cur*2);
		f.resize(cur << 1); g.resize(cur << 1);
		nt.fft(f, 0);
		nt.fft(g, 0);
		rep(i, f.size()) f[i] = nt.mul(f[i], g[i]);
		nt.fft(f, 1);
		f.erase(begin(f), begin(f) + cur);
		f.resize(cur << 1), nt.fft(f, 0);
		rep(i, f.size()) {
			f[i] = mod - nt.mul(f[i], g[i]);
		}
		nt.fft(f, 1);
		ret.insert(end(ret), begin(f), begin(f)+ cur);
		nxt++;
		cur <<= 1;
	}
	assert(ret.size() >= M);
	ret.resize(M);
	return ret;
}
//vecで表される多項式の平方根、x^(M-1)の項までを求めてM長のvectorを返す
//ただし、vec[0] = 0の場合は無理
//整数の平方根求めるのかったるいのでそれはまた後日
//s1(z)^2 = f(z) (mod z)
//sn(z)^2 = f(z) (mod z^n) とする
//s(2n)(z) = 1/2 * (sn(z)+f(z)*sn(z)^-1)
vi sqrt(vi a,int M){
	if(a.empty() || a[0] == 0) return vi();
	//1の場合をやっておく
	vi s[30];
	//今日はvec[0] = 1のことしか考えません
	s[0].pb(1);
	assert(1LL*s[0][0]*s[0][0]%mod == a[0]);
	int cur = 1;
	int nxt = 1;
	vi vec3;
	while(cur < M){
		int nw = min(cur*2,(int)(a.size()));
		int sz = vec3.size();
		vec3.resize(nw,0);
		for(int t=sz;t<nw;t++){
			vec3[t] = a[t];
		}
		s[nxt] = add(s[nxt-1],mul(vec3,inv(s[nxt-1],cur*2)));
		s[nxt] = mul_int(s[nxt],modpow(2,mod-2));
		s[nxt].resize(cur*2);
		nxt++;
		cur *= 2;
	}
	s[nxt-1].resize(M);
	assert(s[nxt-1].size() == M);
	return s[nxt-1];
}
//vecで表される多項式のlog()、x^(M-1)の項までを求めてM長のvectorを返す
//ただし、vec[0] = 0の場合は無理
//log(f(x)) = intg(f'(x)/f(x)) = intg(mul(diff(f(x),need+1),inv(f(x),need+1),need+1))
//積分定数は0固定なので、vec[0]!=1のものを噛ませた場合は壊れる
vi log(vi a,int M){
	if(a.empty() || a[0] == 0) return vi();
	vi x = diff(a,M);
	vi y = inv(a,M);
	vi z = mul(x,y,M);
	return intg(z,0,M);
}
//vecで表される多項式のexp()、x^(M-1)の項までを求めてM長のvectorを返す
//ただし、vec[0] != 0の場合は無理
//exp(a)の定数項は必ず1なので、定数項!=1の多項式のlogを噛ませた場合は壊れる
//http://www.csd.uwo.ca/~eschost/publications/BoSc09-final.pdf
vi exp(vi a,int M){
	if(a.empty() || a[0] != 0) return vi();
	vi f={1},g={1},q,aa;
	int m = 1;
	vi h = diff(a);
	while(m<=M){
		g = sub(mul_int(g,2,m),mul(mul(f,g,m),g,m),m);
		while(aa.size() < 2*m){
			if(aa.size() >= a.size()) aa.pb(0);
			else aa.pb(a[aa.size()]);
		}
		if(m>1){
			vi w = add(q,mul(g,sub(diff(f,2*m-1),mul(f,q,2*m-1),2*m-1),2*m-1),2*m-1);
			f = add(f,mul(f,sub(aa,intg(w,0,2*m),2*m),2*m),2*m);
		}
		else{
			vi w = mul(g,diff(f,2*m-1),2*m-1);
			f = add(f,mul(f,sub(aa,intg(w,0,2*m),2*m),2*m),2*m);
		}
		m*=2;
		while(q.size() < m-1){
			if(q.size() >= h.size()) q.pb(0);
			else q.pb(h[q.size()]);
		}
	}
	f.resize(M);
	assert(f.size() == M);
	return f;
}
//o(ans?"Yes":"No");
void solve(){
	int n,k;
	cin >> n >> k;
	make();
	ll ans = C(2*n, n);
	if(k == 1);
	else if(k == 2) ans = (ans+mod-2) % mod;
	else{
		//k-3, k-2, k-1
		vc<int>pl[3];
		rep(i, 3){
			pl[i].resize(k/2+2, 0);
			for(int x=0;x<k;x++){
				int a = C(k-2+i-x, x);
				if(a == 0) break;
				pl[i][x] = (x%2==1?mod-a:a)%mod;
			}
		}
		auto oo = inv(pl[1],n+2);
		auto tt = inv(pl[2],n+2);
		pl[0] = mul(pl[0], oo);
		pl[1] = mul(pl[1], tt);
		for(int i=1;i<=n;i++){
			ans -= 1LL*pl[0][i-1]*2*i%mod*pl[1][n-i]%mod;
		}
		ans = (ans%mod+mod)%mod;
	}
	o(ans);
}
signed main(){
	cin.tie(0);
	ios::sync_with_stdio(0);
	cout<<fixed<<setprecision(20);
	int t; t = 1; //cin >> t;
	while(t--) solve();
}