#pragma GCC optimize("Ofast")

#include "bits/stdc++.h"


#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep1(i, n) for (int i = 1; i < (n); ++i)
#define rep1n(i, n) for (int i = 1; i <= (n); ++i)
#define repr(i, n) for (int i = (n) - 1; i >= 0; --i)
#define pb push_back
#define eb emplace_back
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define each(x, a) for (auto &x : a)
#define ar array
#define vec vector
#define range(i, n) rep(i, n)

using namespace std;

using ll = long long;
using ull = unsigned long long;
using ld = long double;
using str = string;
using pi = pair<int, int>;
using pl = pair<ll, ll>;

using vi = vector<int>;
using vl = vector<ll>;
using vpi = vector<pair<int, int>>;
using vvi = vector<vi>;

int Bit(int mask, int b) { return (mask >> b) & 1; }

template<class T>
bool ckmin(T &a, const T &b) {
    if (b < a) {
        a = b;
        return true;
    }
    return false;
}

template<class T>
bool ckmax(T &a, const T &b) {
    if (b > a) {
        a = b;
        return true;
    }
    return false;
}

// [l, r)
template<typename T, typename F>
T FindFirstTrue(T l, T r, const F &predicat) {
    --l;
    while (r - l > 1) {
        T mid = l + (r - l) / 2;
        if (predicat(mid)) {
            r = mid;
        } else {
            l = mid;
        }
    }
    return r;
}


template<typename T, typename F>
T FindLastFalse(T l, T r, const F &predicat) {
    return FindFirstTrue(l, r, predicat) - 1;
}

const int INFi = 2e9;
const ll INF = 2e18;


struct convex_hull_trick {
    struct Line {
        ld k, b;

        ld get(ll x) {
            return k * x + b;
        }
    };

    vector<ld> xx;
    vector<Line> lines;
    int ptr = 0;

    ld intersect(Line &a, Line &b) {
        if (a.k == b.k) {
            if (a.b > b.b) return -INF;
            return INF;
        }
        // x = (a.b - b.b) / (b.k - a.k)
        return (a.b - b.b) / (b.k - a.k);
    }

    void add(ld k, ld b) {
        Line A = {k, b};
        while (!lines.empty() && intersect(A, lines.back()) <= xx.back()) {
            xx.pop_back();
            lines.pop_back();
        }
        if (lines.empty()) {
            xx.push_back(-INF);
        } else {
            xx.push_back(intersect(A, lines.back()));
        }
        lines.push_back(A);
//        ptr = min(ptr, )
    }

    ld get(ld x) {
        if (xx.empty()) return -INF;
        int i = upper_bound(all(xx), x) - xx.begin();
        return lines[i - 1].get(x);
    }
};

void solve() {
    int n; cin >> n;
    vector<ld> p(n);
    rep(i, n) cin >> p[i];

    convex_hull_trick cht;
    vector<ld> dp(n);
    ld ans = 0;
    for(int i = n - 1; i >= 0; --i) {
        ld val = p[i] * cht.get(-(i + 1));
        val = max(val, p[i] * (i + 1));
        dp[i] = val;
        ckmax(ans, val);
        cht.add((p[i] - 1), val);
    }

    cout << ans << '\n';
}

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout << setprecision(12) << fixed;
    int t = 1;
//    cin >> t;
    rep(i, t) {
        solve();
    }
    return 0;
}