#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define FOR(i,a,b) for (int i = (a); i < (b); i++)
using namespace std;
using namespace __gnu_pbds;
using ll=long long;
using ld=long double;
using vi=vector<int>;
template<class T> using oset =tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update> ;
//上
struct Line{
    mutable double k,m,p;
    bool operator<(const Line &o) const {return k < o.k;}
    bool operator<(double x) const {return p < x;}
};
struct LineContainer :multiset<Line,less<>>{
    double inf = 1e18;
    double div(double a,double b){
        return a/b;
    }
    bool isect(iterator x,iterator y){
        if(y == end()) return x -> p = inf,0;
        if(x -> k == y -> k) x -> p = x -> m > y -> m? inf:-inf;
        else x -> p  = div(y -> m -x -> m,x -> k - y-> k);
        return x -> p >= y->p;
    }
    void add(double k,double m){
        auto  z = insert({k,m,0}), y = z++,x =y;
        while(isect(y,z)) z = erase(z);
        if(x!=begin() &&isect(--x,y)) isect(x,y = erase(y));
        while((y = x) != begin()&&(--x) -> p >= y->p){
            isect(x,erase(y));
        }
    }
    double query(double x){
        assert(!empty());
        auto l =*lower_bound(x);
        return l.k*x+l.m;
    }
};
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int n;
    cin >> n;
    vector<double> v(n+1);
    FOR(i,0,n) cin >> v[i+1];
    vector<double> dp(n+1);
    dp[n] = n*v[n];
    LineContainer CH;
    CH.add(-v[n],dp[n]);
    for(int i = n-1; i>= 1; i--){
        double mx = CH.query(i);
        dp[i] = v[i] *(mx+(double)(i));
        CH.add(-v[i],dp[i]);
    }
    double re = 0.0;
    for(int i = 1; i<= n;i++) re = max(re,dp[i]);
    cout <<fixed<<setprecision(9)<<re<<'\n';
}