#include <bits/stdc++.h>
#define ll long long
#define enl putchar('\n')
#define all(x) (x).begin(),(x).end()
#define debug(x) printf(" "#x":%d\n",x);
using namespace std;
const int MAXN = 1e5 + 5;
const int inf = 0x3f3f3f3f;
const ll INF = 0x3f3f3f3f3f3f3f3f;
const int mod = 998244353;
typedef pair<int, int> pii;
char buf[1 << 21], * p1 = buf, * p2 = buf, obuf[1 << 21], * o = obuf, of[35];
#define gc()(p1==p2&&(p2=(p1=buf)+fread(buf,1,1<<21,stdin),p1==p2)?EOF:*p1++)
inline ll qpow(ll a, ll n) { ll res = 1; while (n) { if (n & 1)res = res * a % mod; n >>= 1; a = a * a % mod; }return res; }
template <class T = int>inline T read() { T s = 0, f = 1; char c = gc(); for (; !isdigit(c); c = gc())if (c == '-')f = -1; for (; isdigit(c); c = gc())s = s * 10 + c - '0'; return s * f; }
inline void read(int* a, int n) { for (int i = 1; i <= n; ++i)a[i] = read(); }
inline int inal(char* s) { int n = 0; for (s[0] = gc(); !isalpha(s[0]); s[0] = gc()); for (; isalpha(s[n]); s[++n] = gc()); return s[n] = 0, n; }
inline int indi(char* s) { int n = 0; for (s[0] = gc(); !isdigit(s[0]); s[0] = gc()); for (; isdigit(s[n]); s[++n] = gc()); return s[n] = 0, n; }
inline void outd(auto* a, int n) { for (int i = 1; i <= n; ++i)printf("%d ", a[i]); enl; }
int n, m, q;
bool inC[MAXN];
int stk[MAXN], top;


struct Point {
    ll x, y;
    Point(ll x = 0, ll y = 0) :x(x), y(y) {}
    Point operator -(const Point& b)const { return Point(x - b.x, y - b.y); }
    Point operator +(const Point& b)const { return Point(x + b.x, y + b.y); }
    Point operator *(ll k)const { return Point(x * k, y * k); }
    ll operator ^(const Point& b)const { return x * b.y - y * b.x; }
    ll operator *(const Point& b)const { return x * b.x + y * b.y; }
    ll operator !()const { return sqrt(*this * *this); }
    bool operator <(const Point& b) const { return y - b.y < 0 || (y - b.y == 0 && x - b.x < 0); }
    bool operator ==(const Point& b)const { return !(*this < b) && !(b < *this); }
    bool operator >(const Point& b)const { return b < *this; }
    bool operator <=(const Point& b)const { return !(*this > b); }
    bool operator >=(const Point& b)const { return !(*this < b); }
    bool operator !=(const Point& b)const { return !(*this == b); }
    Point operator /(ll k)const { return Point(x / k, y / k); }
    ll operator ~()const { return atan2(y, x); }
    Point operator -()const { return Point(-x, -y); }
    ll len2()const { return x * x + y * y; }
    ll len()const { return !*this; }
    ll dis(const Point& b)const { return (*this - b).len(); }
    ll dis2(const Point& b)const { return (*this - b).len2(); }
    Point rotate(ll a)const { return Point(x * cos(a) - y * sin(a), x * sin(a) + y * cos(a)); }
    Point rotate(ll a, const Point& o)const { return Point(x * cos(a) - y * sin(a) + o.x, x * sin(a) + y * cos(a) + o.y); }
    Point unit()const { return *this / len(); }
    ll sqr(const Point& b, const Point& c) {
        return (b - *this) ^ (c - *this);
    }
    ll proj(const Point& b, const Point& c) {
        return (b - *this) * (c - *this);
    }
    void rot90() { swap(x, y); x = -x; }
}a[MAXN];


struct polygon {
    int n;
    vector<Point>pt;
    polygon(int _n = 0) :n(_n) { pt.resize(n); }
    polygon(vector<Point> _pt) :pt(_pt) { n = pt.size(); }
    void unit() {
        Point lp = pt[0];
        for (int i = 1; i < n; ++i)pt[i] = pt[i] - lp;
    }
    Point& operator[](const int& i) { return pt[i % n]; }
    Point& back() { return pt.back(); }
    ll area() {
        ll res = 0;
        for (int i = 0; i < n; ++i)
            res += pt[i] ^ pt[(i + 1) % n];
        return abs(res);
    }
};

polygon Andrew() {
    top = 0;
    memset(inC + 1, 0, sizeof(bool) * n);
    sort(a + 1, a + n + 1, [&](Point a, Point b) { return a.x < b.x || (a.x == b.x && a.y < b.y); });
    for (int i = 1; i <= n; ++i) {
        while (top > 1 && ((a[stk[top]] - a[stk[top - 1]]) ^ (a[i] - a[stk[top]])) < 0)
            inC[stk[top--]] = 0;
        stk[++top] = i;
        inC[i] = 1;
    }
    inC[1] = 0;

    int t = top;
    for (int i = n - 1; i >= 1; --i) {
        if (inC[i]) continue;
        while (top > t && ((a[stk[top]] - a[stk[top - 1]]) ^ (a[i] - a[stk[top]])) < 0)
            inC[stk[top--]] = 0;
        stk[++top] = i;
        inC[i] = 1;
    }
    if (!top) return polygon();
    if (top == 1) return polygon({a[1]});
    static bool vis[MAXN];
    polygon res(top - 1);
    for (int i = 1; i <= top; ++i) {
        vis[stk[i]] = 1;
        res[i - 1] = a[stk[i]];
    }
    for (int i = 1, j = 1; i <= n; ++i) {
        if (vis[i]) continue;
        a[j++] = a[i];
    }
    n -= top - 1;
    for (int i = 1; i <= top; ++i) vis[stk[i]] = 0;
    return res;
}

void solve() {
    n = read();
    for (int i = 1; i <= n; ++i) {
        a[i].x = read(), a[i].y = read();
    }
    polygon A = Andrew();
    polygon B = Andrew();
    if (A.n < 3 || B.n == 0) return cout << "-1\n", void();
    ll sum = A.area(), ans = INF;
    if (B.n < 3) {
        for (auto p : B.pt)
            for (int i = 0; i < A.n; ++i)
                ans = min(ans, abs(p.sqr(A[i], A[i + 1])));
        return cout << sum - ans << '\n', void();
    }
    int p = 0;
    for (int i = 0; i < B.n; ++i)
        if (abs(B[p].sqr(A[0], A[1])) > abs(B[i].sqr(A[0], A[1]))) p = i;
    for (int i = 0; i < A.n; ++i) {
        while (abs(B[p].sqr(A[i], A[i + 1])) > abs(B[p + 1].sqr(A[i], A[i + 1]))) p++;
        ans = min(ans, abs(B[p].sqr(A[i], A[i + 1])));
    }
    cout << sum - ans << '\n';
}


signed main(signed argc, char const* argv[]) {
    clock_t c1 = clock();
#ifdef LOCAL
    freopen("in.in", "r", stdin);
    freopen("out.out", "w", stdout);
#endif
    //=============================================================
    ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
    int TxT = read();
    while (TxT--)
        solve();
    //=============================================================
#ifdef LOCAL
    end :
    cerr << "Time Used:" << clock() - c1 << "ms" << endl;
#endif
    return 0;
}