#include<iostream>

#include<cstdio>

#include<cstring>

#include<algorithm>

#include<cmath>

#define File(s) freopen(s".in","r",stdin),freopen(s".out","w",stdout)

#define maxn 50010

using namespace std;

typedef long long llg;

struct data{

    llg x,y;

}s[maxn];

int n,L,d[maxn],l,r;

llg f[maxn],w[maxn];

int getint(){

    int w=0;bool q=0;

    char c=getchar();

    while((c>'9'||c<'0')&&c!='-') c=getchar();

    if(c=='-') c=getchar(),q=1;

    while(c>='0'&&c<='9') w=w*10+c-'0',c=getchar();

    return q?-w:w;

}

double xie(data a,data b){return (double)(b.y-a.y)/(double)(b.x-a.x);}

llg ji(llg x){return x*x;}

int main(){

    File("a");

    n=getint(); L=getint()+1;

    for(int i=1;i<=n;i++){

        w[i]=getint(); w[i]+=w[i-1];

        while(l<r && xie(s[d[l]],s[d[l+1]])<(w[i]+i)*2) l++;

        f[i]=f[d[l]]+ji(w[i]+i-w[d[l]]-d[l]-L);

        s[i].x=w[i]+i; s[i].y=f[i]+ji(w[i]+i)+2*(w[i]+i)*L;

        while(l<r && xie(s[d[r-1]],s[d[r]])>=xie(s[d[r]],s[i])) r--;

        d[++r]=i;

    }

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

}