#include<iostream>
#include<cstdio>
#include<fstream>
#include<queue>
#include<algorithm>
#define maxn 500005
#define fopen(x, y) freopen(x".in", "r", stdin); freopen(y".out", "w", stdout);
//#define int long long
#define fi first
#define se second
#ifdef int
#define inf 0x3f3f3f3f3f3f3f3fll
#else
#define inf 0x3f3f3f3f
#endif

using namespace std;

template<typename _Tp>
struct Stack {
	size_t tp;
	_Tp dat[maxn];
	Stack() {
		tp = 0;
	}
	bool empty() {
		return tp;
	}
	size_t size() {
		return tp;
	}
	void push(_Tp x) {
		dat[tp++] = x;
	}
	_Tp top() {
		return dat[tp - 1];
	}
	_Tp pop() {
		return dat[--tp];
	}
	_Tp& operator[](int i) {
		return i < 0 ? dat[tp + i] : dat[i];
	}
};

Stack<pair<long double, long double> > stk; 

int n;
long double g[maxn], p[maxn];

long double k(int x) {
	return (stk[x + 1].fi - stk[x].fi) / (stk[x + 1].se - stk[x].se);
}

void work() {
	cin >> n; 
	for(int i = 1; i <= n; i++) {
		cin >> p[i];
	}
	g[n] = p[n] * n;
	stk.push({g[n], p[n]});
	for(int i = n - 1; i >= 1; i--) {
		int l = 0, r = stk.size() - 1;
		while(l < r) {
			int mid = (l + r) >> 1;
			if(k(mid) < i) r = mid;
			else l = mid + 1;
//			cout << 1 << endl;
		}
		g[i] = p[i] * (i + stk[l].fi - stk[l].se * i);
//		cout << i << ' ' << p[i] << ' ' << g[i] << "<-" << stk[l].se << ' ' << stk[l].fi << endl;
		stk.push({g[i], p[i]});
		while(stk.size() >= 3) {
			if(k(-2) > k(-3)) {
				stk[-2] = stk[-1]; stk.pop();
			}
			else break;
		}
	}
	long double mx = 0;
	for(int i = 1; i <= n; i++) mx = max(mx, g[i]);
	printf("%.12Lf\n", mx);
}

signed main() {
	ios::sync_with_stdio(false); cin.tie(0);
	int _ = 1;
//	cin >> _;
	while(_--) work();
}