TRILAND

#include <bits/stdc++.h>
using namespace std;

using ll = long long;
using ld = long double;
using pii = pair<int, int>;

const int maxN = 3e3 + 5;
const int INF = 1e9 + 7;
const double eps = 1e-8;

struct point {
    long long x, y;
};

bool xetx(point a, point b) { return (a.x < b.x) || (a.x == b.x && a.y < b.y); }
bool xety(point a, point b) { return (a.y < b.y) || (a.y == b.y && a.x < b.x); }

ll area(point a, point b, point c) {
    return a.x * (b.y - c.y) + b.x * (c.y - a.y) + c.x * (a.y - b.y);
}

bool isCW(point a, point b, point c) { return area(a, b, c) < 0; }
bool isCCW(point a, point b, point c) { return area(a, b, c) > 0; }

int n;
point p[maxN];

ll ans = 0;
vector<point> hull;

void convexHull(vector<point> &a) {
    vector<point> up, down;
    up.push_back(p[1]);
    down.push_back(p[1]);

    for (int i = 1; i <= n; ++i) {
        if (i == n || isCW(p[1], p[i], p[n])) {
            while (up.size() > 1 && !isCW(up[up.size() - 2], up[up.size() - 1], p[i]))
                up.pop_back();
            up.push_back(p[i]);
        }

        if (i == n || isCCW(p[1], p[i], p[n])) {
            while (down.size() > 1 && !isCCW(down[down.size() - 2], down[down.size() - 1], p[i]))
                down.pop_back();
            down.push_back(p[i]);
        }
    }

    for (int i = 0; i < up.size(); ++i)
        a.push_back(up[i]);
    for (int i = down.size() - 2; i > 0; --i)
        a.push_back(down[i]);
}

void solve() {
    for (int i = 0; i < hull.size() - 2; ++i) {
        int k = i + 2;
        for (int j = i + 1; j < hull.size() - 1; ++j) {
            if (j >= k) k = j + 1;
            ll cur = abs(area(hull[i], hull[j], hull[k]));
            while (k < hull.size() - 1) {
                ll tmp = abs(area(hull[i], hull[j], hull[k + 1]));
                if (cur < tmp) cur = tmp, ++k;
                else break;
            }
            ans = max(ans, cur);
        }
    }
    cout << (ans >> 1LL) << (ans % 2 ? ".5\n" : ".0\n");
}

int main() {
#ifdef LOCAL
    freopen("in1.txt", "r", stdin);
#else
    freopen("TRILAND.inp", "r", stdin);
    freopen("TRILAND.out", "w", stdout);
#endif
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    cin >> n;
    for (int i = 1; i <= n; ++i)
        cin >> p[i].x >> p[i].y;
    sort(p + 1, p + n + 1, [](point a, point b) {
        if (a.x == b.x) return a.y < b.y;
        return a.x < b.x;
    });

    convexHull(hull);
    solve();

    return 0;
}