#include<iostream>
#include<cstring>
using namespace std;
const int mod=998244353;
struct matrix
{
	int a[4][4],r,c;
	matrix(){memset(a,0,sizeof(a));r=c=0;}
	matrix(int _r,int _c){r=_r;c=_c;memset(a,0,sizeof(a));}
};
matrix operator*(matrix a,matrix b)
{
	matrix c(a.r,b.c);
	for(int i=0;i<a.r;++i)
	{
		for(int j=0;j<b.c;++j)
		{
			__int128 tt=0;
			for(int k=0;k<a.c;++k)
			{
				tt+=1ll*a.a[i][k]*b.a[k][j];
			}
			c.a[i][j]=tt%mod;
		}
	}
	return c;
}
matrix qpow(matrix bs,int ex)
{
	matrix ans(bs.r,bs.c);
	for(int i=0;i<bs.r;++i)ans.a[i][i]=1;
	while(ex)
	{
		if(ex&1)ans=ans*bs;
		bs=bs*bs;ex>>=1;
	}
	return ans;
}
int n,m,ans;
int solve(int m)
{
	if(!m)
	{
		return 1;
	}
	if(m&1)
	{
		return (long long)
		ans*solve(m>>1)%mod;
	}
	return (solve(m>>1)+solve((m>>1)-1))%mod;
}
matrix M(4,4);
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	cin>>n>>m;
	for(int i=0;i<4;i++)
	{
		for(int j=0;j<2;j++)
		{
			if(((i>>1)&j)^(i&1))
			{
				M.a[((i&1)<<1)|j][i]++;
			}
		}
	}
	M=qpow(M,n-2);
	for(int i=0;i<4;i++)
	{
		for(int j=0;j<4;j++)
		{
			bool t1=i>>1,t2=i&1,t3=j>>1,t4=j&1;
			if(((t1&t3)^t2)&&((t2&t4)^t3))
			{
				ans=(ans+M.a[i][j])%mod;
			}
		}
	}
	cout<<solve(m)<<endl;
	return 0;
}