#include<bits/stdc++.h>
using namespace std;
#define int long long

inline int read()
{
	int x=0,f=1;
	char c=getchar();
	while(c<'0' || c>'9')
	{
		if(c=='-') f=-1;
		c=getchar();
	}
	while(c>='0' && c<='9')
	{
		x=x*10+c-'0';
		c=getchar();
	}
	return x*f;
}

const int mod=998244353;

inline int power(int x,int y)
{
	int ans=1;
	for(;y;y>>=1)
	{
		if(y&1) ans=ans*x%mod;
		x=x*x%mod;
	}
	return ans;
}

const int N=1e6+5;
int n,m;
int f[N];
int s[N];

signed main()
{
	n=read(); m=read();
	f[0]=1;
	for(int i=1;i<=n;i++)
	{
		int val=power(m,i);
		f[i]=val;
		f[i]=(f[i]-val*s[i/2]%mod+mod)%mod;
		s[i]=(s[i-1]+f[i]*power(power(m,2*i)%mod,mod-2)%mod)%mod;
	}
	int ans=0;
	for(int i=1;i*2<n;i++)
		ans=(ans+f[i]*power(m,n-i*2)%mod)%mod;
	cout<<ans<<endl;
	return 0;
}