#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef double db;
typedef pair <int, int> pii;
typedef pair <ll, ll> pll;
#define fir first
#define sec second
typedef vector <int> vi;
typedef vector <ll> vl;

#ifdef LCX
#define msg(args...) fprintf(stderr, args)
#else
#define msg(...) void()
#endif

int sgn(const ll &x) {
    if (x == 0) return 0;
    return x > 0 ? 1 : -1;
}

struct Point {
    ll x, y;
    Point() : x(0), y(0) {}
    template <typename __Tp1, typename __Tp2>
    Point(__Tp1 x, __Tp2 y) : x(x), y(y) {}

    Point operator + (const Point &p) const { return Point(x + p.x, y + p.y); }
    Point operator - () const { return Point(-x, -y); }
    Point operator - (const Point &p) const { return Point(x - p.x, y - p.y); }
    Point operator * (const db &k) const { return Point(x * k, y * k); }
    Point operator / (const db &k) const { return Point(x / k, y / k); }

    bool operator < (const Point &p) const {
        if (sgn(x - p.x) != 0)
            return sgn(x - p.x) < 0;
        return sgn(y - p.y) < 0;
    }
    bool operator > (const Point &p) const {
        if (sgn(x - p.x) != 0)
            return sgn(x - p.x) > 0;
        return sgn(y - p.y) > 0;
    }
    bool operator <= (const Point &p) const {
        if (sgn(x - p.x) != 0)
            return sgn(x - p.x) < 0;
        return sgn(y - p.y) <= 0;
    }
    bool operator >= (const Point &p) const {
        if (sgn(x - p.x) != 0)
            return sgn(x - p.x) > 0;
        return sgn(y - p.y) >= 0;
    }
    bool operator == (const Point &p) const {
        return sgn(x - p.x) == 0 && sgn(y - p.y) == 0;
    }
    bool operator != (const Point &p) const {
        return sgn(x - p.x) != 0 || sgn(y - p.y) != 0;
    }
};
ll cross(const Point &p, const Point &q) { return p.x * q.y - p.y * q.x; }

struct Line {
    Point a, v;
    #ifdef RESTORE_ANGLE_IN_STRUCTURE
    db ang;
    #endif
    Line() : a(), v() {
        #ifdef RESTORE_ANGLE_IN_STRUCTURE
        ang = 0;
        #endif
    }
    Line(const Point &a, const Point &v) : a(a), v(v) {
        #ifdef RESTORE_ANGLE_IN_STRUCTURE
        ang = angle(v);
        #endif
    }
};
Line toLine(const Point &s, const Point &e) { return Line(s, e - s); }
int side(const Point &p, const Line &l) { return sgn(cross(l.v, p - l.a)); }
// p is on the left (counterclockwise) side of l if side(p, l) == 1

namespace Convex {
const int maxn = 1e5 + 10;
Point tmp[maxn];
int tot;
int build(Point *a, int &n) {
    sort(a + 1, a + n + 1);
    n = unique(a + 1, a + n + 1) - a - 1;
    if (n <= 2) return n;
    tmp[tot = 1] = a[1];
    for (int i = 2; i <= n; ++i) {
        while (tot > 1 && side(a[i], toLine(tmp[tot - 1], tmp[tot])) <= 0) --tot;
        tmp[++tot] = a[i];
    }
    int lim = tot;
    for (int i = n - 1; i >= 1; --i) {
        while (tot > lim && side(a[i], toLine(tmp[tot - 1], tmp[tot])) <= 0) --tot;
        tmp[++tot] = a[i];
    }
    n = tot - 1;
    for (int i = 1; i <= tot; ++i) a[i] = tmp[i];
    return lim;
}
// return the index of the upper right corner
}

const int maxn = 1e5 + 10;
int n;
Point a[maxn], tmp[maxn];
void go(int &p, const Point &v) {
    while (side(a[p + 1], Line(a[p], v)) < 0 ||
            side(a[p - 1], Line(a[p], v)) < 0) p = p % n + 1;
}
void work() {
    scanf("%d", &n);
    for (int i = 1; i <= n; ++i)
        scanf("%lld%lld", &a[i].x, &a[i].y),
        tmp[i] = a[i];
    int nn = n;
    Convex::build(a, n);
    a[n + 1] = a[1], a[0] = a[n];
    if (n <= 2) return printf("0\n"), void();
    ll ans = 0;
    if (n == 3) {
        bool vis[4] = {0, 0, 0, 0};
        ll all = cross(a[2] - a[1], a[3] - a[1]);
        for (int i = 1; i <= nn; ++i) {
            int flg = 0;
            for (int j = 1; j <= 3; ++j)
                if (!vis[j] && a[j] == tmp[i]) flg = 1, vis[j] = 1;
            if (!flg) {
                for (int j = 1; j <= 3; ++j)
                    ans = max(ans, all - cross(a[j] - tmp[i], a[j + 1] - tmp[i]));
            }
        }
    }
    else {
        for (int i = 1, j = 1, k = 1, l = 1; i <= n; ++i) {
            go(j, a[i] - a[i + 1]);
            go(k, a[j] - a[i]);
            go(l, a[i] - a[j]);
            ans = max(ans, cross(a[k] - a[i], a[j] - a[i]) +
                cross(a[j] - a[i], a[l] - a[i]));
        }
    }
    if (ans & 1) printf("%lld.5\n", ans / 2);
    else printf("%lld\n", ans / 2);
}

int main() {
    int T; scanf("%d", &T);
    while (T --> 0) work();
    return 0;
}