#include <bits/stdc++.h>using namespace std;#define maxn 50005#define ll long longll que[maxn],sum[maxn],dp[maxn],n,l,ai[maxn],a;inline void in(ll &now){    char Cget=getchar();now=0;    while(Cget>‘9‘||Cget<‘0‘)Cget=getchar();    while(Cget>=‘0‘&&Cget<=‘9‘)    {        now=now*10+Cget-‘0‘;        Cget=getchar();    }}ll G(ll now){    return sum[now]+now;}ll Y(ll x,ll y){    return dp[x]+pow(G(x)+a,2)-dp[y]-pow(G(y)+a,2);}ll X(ll x,ll y){    return 2*(G(x)-G(y));}int main(){    in(n),in(l),a=l+1;ll h=0,tail=0;    for(ll i=1;i<=n;i++) in(ai[i]),sum[i]=sum[i-1]+ai[i];    for(ll i=1;i<=n;i++)    {        while(h<tail&&Y(que[h+1],que[h])<=G(i)*X(que[h+1],que[h])) ++h;        dp[i]=dp[que[h]]+(G(i)-G(que[h])-a)*(G(i)-G(que[h])-a);        while(h<tail&&Y(i,que[tail])*X(que[tail],que[tail-1])<=Y(que[tail],que[tail-1])*X(i,que[tail])) --tail;        que[++tail]=i;    }    cout<<dp[n];    return 0;}