#include <bits/stdc++.h>
#define int long long

using namespace std;

const int mod = 998244353;
int n, k, a[1000005], pre[1000005], pre2[1000005], ans, p;

signed main()
{
	cin >> n >> k;
	for (int i = 1 ; i <= n ; i ++)
	{
		cin >> a[i];
		if (a[i] < 0)
		{
			p = i;
		}
		pre[i] = (pre[i - 1] + a[i] % mod + mod) % mod;
		pre2[i] = (pre2[i - 1] + a[i] * a[i] % mod + mod) % mod;
	}
	for (int i = 1 ; i <= k ; i ++)
	{
		while (-a[p] - 1 < a[p] + i && p)
		{
			p --;
		}
		ans = (ans + (pre2[p] % mod + 2 * pre[p] % mod + p + mod) % mod + ((pre2[n] - pre2[p]) % mod + 2 * i * ((pre[n] - pre[p] + mod)) + mod + i * i * (n - p) % mod % mod) % mod + mod) % mod;
	}
	cout << ans;
}