#include<bits/stdc++.h>
using namespace std;
namespace Polynomial
{
	using ll=long long;
	using poly=vector<ll>;
	const ll mod=998244353;
	ll ksm(ll a,ll b)
	{
		ll ans=1;
		while(b)
		{
			if(b&1) ans=ans*a%mod;
			b>>=1;
			a=a*a%mod;
		}
		return ans;
	}
	inline int sz(const poly &p)
	{
		return p.size();
	}
	const poly operator +(const poly &a,const poly &b)
	{
		int p=sz(a),q=sz(b);
		int n=max(p,q);
		poly ret(n,0);
		for(int i=0;i<n;i++)
		{
			if(i<p) ret[i]+=a[i];
			if(i<q) ret[i]+=b[i];
			if(ret[i]>=mod) ret[i]-=mod;
		}
		return ret;
	}
	const poly operator -(const poly &a,const poly &b)
	{
		int p=sz(a),q=sz(b);
		int n=max(p,q);
		poly ret(n,0);
		for(int i=0;i<n;i++)
		{
			if(i<p) ret[i]+=a[i];
			if(i<q) ret[i]+=mod-b[i];
			if(ret[i]>=mod) ret[i]-=mod;
		}
		return ret;
	}
	poly operator *(poly a,poly b)
	{
		const ll g=3;
		int len=sz(a)+sz(b);
		int m=1;
		while(m<sz(a)+sz(b)) m*=2;
		a.resize(m);
		b.resize(m);
		vector<int> rev(m);
		for(int i=0;i<m;i++)
			rev[i]=(rev[i>>1]>>1)|((i&1)*(m>>1));
		for(int i=0;i<m;i++)
			if(rev[i]<i)
			{
				swap(a[i],a[rev[i]]);
				swap(b[i],b[rev[i]]);
			}
		for(int i=1;i<m;i<<=1)
		{
			ll gn=ksm(g,(mod-1)/i/2);
			for(int j=0;j<m;j+=(i<<1))
			{
				ll g0=1;
				for(int k=0;k<i;k++,g0=g0*gn%mod)
				{
					{
						ll x=a[j+k],y=g0*a[i+j+k]%mod;
						a[j+k]=(x+y)%mod;
						a[i+j+k]=(x+mod-y)%mod;
					}
					{
						ll x=b[j+k],y=g0*b[i+j+k]%mod;
						b[j+k]=(x+y)%mod;
						b[i+j+k]=(x+mod-y)%mod;
					}
				}
			}
		}
		for(int i=0;i<m;i++)
			a[i]=a[i]*b[i]%mod;
		for(int i=0;i<m;i++)
			if(rev[i]<i)
				swap(a[i],a[rev[i]]);
		for(int i=1;i<m;i<<=1)
		{
			ll gn=ksm(g,(mod-1)/i/2*(mod-2));
			for(int j=0;j<m;j+=(i<<1))
			{
				ll g0=1;
				for(int k=0;k<i;k++,g0=g0*gn%mod)
				{
					ll x=a[j+k],y=g0*a[i+j+k]%mod;
					a[j+k]=(x+y)%mod;
					a[i+j+k]=(x+mod-y)%mod;
				}
			}
		}
		ll val=ksm(m,mod-2);
		for(int i=0;i<m;i++)
			a[i]=a[i]*val%mod;
		a.resize(len-1);
		return a;
	}
	poly inv(poly p,int deg)
	{
		p.resize(deg);
		if(deg==1) return {ksm(p[0],mod-2)};
		poly w=inv(p,(deg+1)/2);
		poly g=w+w-p*w*w;
		g.resize(deg);
		return g;
	}
	poly deriv(poly p)
	{
		for(int i=0;i<sz(p);i++)
			p[i]=p[i]*i%mod;
		p.erase(p.begin());
		return p;
	}
	poly integ(poly p)
	{
		p.insert(p.begin(),0);
		for(int i=0;i<sz(p);i++)
			p[i]=p[i]*ksm(i,mod-2)%mod;
		return p;
	}
	poly ln(poly p)
	{
		return integ(deriv(p)*inv(p,sz(p)));
	}
	poly exp(poly p,int deg)
	{
		p.resize(deg);
		if(deg==1)
			return {1};
		poly g=exp(p,(deg+1)/2);
		g=g*(poly{1}-ln(g)+p);
		g.resize(deg);
		return g;
	}
	const poly operator %(poly a,poly b)
	{
		if(sz(a)<sz(b)) return a;
		int n=sz(a),m=sz(b);
		int d=n-m+1;
		poly a2=a,b2=b;
		reverse(a2.begin(),a2.end());
		reverse(b2.begin(),b2.end());
		a2.resize(d);
		b2.resize(d);
		poly q=a2*inv(b2,d);
		q.resize(d);
		reverse(q.begin(),q.end());
		q=a-b*q;
		q.resize(m-1);
		return q;
	}
	const poly operator /(poly a,poly b)
	{
		if(sz(a)<sz(b)) return a;
		int n=sz(a),m=sz(b);
		int d=n-m+1;
		poly a2=a,b2=b;
		reverse(a2.begin(),a2.end());
		reverse(b2.begin(),b2.end());
		a2.resize(d);
		b2.resize(d);
		poly q=a2*inv(b2,d);
		q.resize(d);
		reverse(q.begin(),q.end());
		return q;
	}
}
using namespace Polynomial;
ll fact[200200],rfact[200200];
ll S[200200];
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	fact[0]=1;
	for(int i=1;i<200200;i++)
		fact[i]=fact[i-1]*i%mod;
	for(int i=0;i<200200;i++)
		rfact[i]=ksm(fact[i],mod-2);
	int n;
	ll m;
	cin>>n>>m;
	poly f(n+1),g(n+1);
	for(int i=0;i<=n;i++)
		f[i]=fact[n]*rfact[i]%mod*max(0,n/2-i)%mod;
	for(int i=0;i<=n;i++)
		g[i]=rfact[i]*((i&1)?(mod-1):1)%mod;
	poly h=f*g;
	for(int i=0;i<=n;i++)
		h[i]=h[i]*ksm(m,n-i)%mod*rfact[n-i]%mod;
	poly B=exp(poly{0,1},n+n+3);
	B.erase(B.begin());
	B=inv(B,n+n+3);
	B.resize(n+2);
	poly C(n+2);
	for(int i=1;i<=n+1;i++)
		C[i]=ksm(m,i)*rfact[i]%mod;
	poly D=B*C;
	for(int i=0;i<=n;i++)
		S[i]=D[i+1]*fact[i]%mod;
	ll ans=0;
	for(int i=0;i<=n;i++)
		ans=(ans+S[i]*h[i])%mod;
	ans=(ksm(m,n)*(n/2)%mod*(m+1)%mod-ans-ans+mod+mod)%mod;
	cout<<ans<<'\n';
	return 0;
}