#include<cstdio>
#include<algorithm>
using namespace std;
const int N=5e5+5;
const int mod=998244353;
int n,m,a[N],f[N],inv[N];
int read()
{
	int res,f=1;
	char ch;
	while((ch=getchar())<'0'||ch>'9')
	if(ch=='-')
	f=-1;
	res=ch^48;
	while((ch=getchar())>='0'&&ch<='9')
	res=(res<<1)+(res<<3)+(ch^48);
	return res*f;
}
int main()
{
//	freopen("ex_a4.in","r",stdin);
	int i,ans=0;
	n=read();m=read();
	for(i=1;i<=n;i++)
	a[i]=read();
	f[1]=1;inv[1]=1;
	for(i=2;i<=n;i++)
	{
		inv[i]=1ll*(mod-mod/i)*inv[mod%i]%mod;
		f[i]=1ll*f[i-1]*(m+i-1)%mod*inv[i-1]%mod;
	}
	for(i=1;i<=n;i++)
	ans=(ans+1ll*a[i]*f[i]%mod*f[n+1-i]%mod)%mod;
	printf("%d",ans);
	return 0;
}