#include<bits/stdc++.h>
using namespace std;
long long n,m,k,l,k4[2000007];
double eps=1e-8,ak[1000007],ab[1000007],ans,f[1000007],a[1000007],ss;
double gy(int z,int x){return ak[z]*x+ab[z];}
void X(int x,int y,int z,long long h){
	if(!k4[z]){
		k4[z]=h;
		return;
	}
	int mid=(x+y)/2;
	if(gy(h,mid)>gy(k4[z],mid))swap(h,k4[z]);
	if(gy(h,x)>gy(k4[z],x))X(x,mid,z*2,h);
	if(gy(h,y)>gy(k4[z],y))X(mid+1,y,z*2+1,h);
}
void Q(int x,int y,int z,int h){
	if(!k4[z])return;
	ans=max(ans,gy(k4[z],h));
	if(x==y)return;
	int mid=(x+y)/2;
	if(x<=h&&h<=mid)Q(x,mid,z*2,h);
	else Q(mid+1,y,z*2+1,h);
}
int main(){
	cin>>n;
	for(int i=1;i<=n;i++)scanf("%lf",&a[i]);
	for(int i=n;i>=1;i--){
		ans=0;Q(1,n,1,i);
		f[i]=ans+i;
		ak[i]=-a[i],ab[i]=a[i]*f[i];
		X(1,n,1,i);
		ss=max(ss,a[i]*f[i]);
	}
	printf("%.12lf",ss);
}