#include<bits/stdc++.h>
using namespace std;
const int N=5e5+10;
typedef long long ll;
int n;
ll sum[N],Sum[N],a[N],ans;
struct point{
	ll x,y;
	point(ll X=0,ll Y=0){x=X;y=Y;}
	point operator - (point a){return point(x-a.x,y-a.y);}
	ll operator * (point a){return x*a.y-y*a.x;}
}p[N],q[N],Q[N],A[N];
int head,tail;
ll calc(point p,point q){
	return p.x*q.x+p.y+q.y;
}
bool cmp(point x,point y){return x.x<y.x;}
void solve(int l,int r){
	if (l==r) return;
	int mid=(l+r)>>1;
	solve(l,mid);
	solve(mid+1,r);
	head=1;tail=0;
	for (int i=l;i<=mid;i++){
		for (;tail>1&&(Q[tail]-Q[tail-1])*(p[i]-Q[tail])>0;tail--);
		Q[++tail]=p[i];
	}
	for (int i=mid+1;i<=r;i++){
		for (;head<tail&&calc(q[i],Q[head])<calc(q[i],Q[head+1]);head++);
		ans=max(ans,calc(q[i],Q[head]));
	}
	merge(p+l,p+mid+1,p+mid+1,p+r+1,A+l,cmp);
	for (int i=l;i<=r;i++) p[i]=A[i];
	merge(q+l,q+mid+1,q+mid+1,q+r+1,A+l,cmp);
	for (int i=l;i<=r;i++) q[i]=A[i];
}
int main()
{
	scanf("%d",&n);
	for (int i=1;i<=n;i++) scanf("%lld",&a[i]);
	for (int i=1;i<=n;i++) sum[i]=sum[i-1]+a[i];
	for (int i=1;i<=n;i++) Sum[i]=Sum[i-1]+a[i]*a[i];
	for (int i=0;i<n;i++) p[i]=point(sum[i],sum[i]*sum[i]+Sum[i]);
	for (int i=1;i<=n;i++) q[i]=point(-2*sum[i],sum[i]*sum[i]-Sum[i]);
	solve(0,n);
	/*for (int l=0;l<n;l++)
	for (int r=l+1;r<=n;r++)
		ans=max(ans,calc(p[l],q[r]));*/
	cout<<ans/2<<endl; 
	return 0;
}