#include<iostream>

#include<cstdio>

#include<cstring>

using namespace std;

typedef double db;

int const maxn=;

int n,l,q[maxn];

db sum[maxn],f[maxn];

db a(int i){return sum[i]+i;}

db b(int i){return sum[i]+i+l+;}

db y(int i){return f[i]+b(i)*b(i);}

db x(int i){return b(i);}

db slope(int i,int j){return (y(i)-y(j))/(x(i)-x(j));}

int main()

{

    scanf("%d%d",&n,&l);

    for(int i=;i<=n;i++)

    {

        scanf("%lf",&sum[i]);

        sum[i]+=sum[i-];

    }

    int head=,tail=;

    for(int i=;i<=n;i++)

    {

        while(head<tail&&slope(q[head],q[head+])<*a(i))head++;

//        f[i]=y(q[head])-2*a(i)*b(q[head])+a(i)*a(i);

        f[i]=f[q[head]]+(a(i)-b(q[head]))*(a(i)-b(q[head]));

        while(head<tail&&slope(q[tail-],q[tail])>slope(q[tail-],i))tail--;

        q[++tail]=i;

    }

    printf("%lld",(long long)f[n]);

    return ;

}