#include<bits/stdc++.h>
using namespace std;
const int mod=998244353;
long long n,m,a[10000001];
long long sum1,sum2,tmp,sum3;
int main()
{
	cin>>n>>m;
	for(int i=1;i<=n;i++)
	{
		cin>>a[i];
		if(a[i]<0) sum1+=(a[i]+1)*(a[i]+1)%mod;
		else
		{
			if(!tmp) tmp=i;
			sum2+=(a[i])*(a[i])%mod;
			sum3+=(a[i]+1)%mod*(a[i]+1)%mod-a[i]%mod*a[i]%mod; 
		}
	}
	long long ans=0,len=n-tmp+1,gc=sum3;
	ans+=sum1*(m%mod)%mod;
	sum2+=sum3;
	for(int i=1;i<=m;i++)
	{
		sum2%=mod; 
		ans%=mod;
		ans+=sum2; 
		gc+=len*2;
		gc%=mod;
		sum2+=gc;
	} 
	cout<<ans%mod;
} 

W