#include <bits/stdc++.h>
using namespace std;
#define all(v) (v).begin(),(v).end()
#define pb(a) push_back(a)
#define rep(i, n) for(int i=0;i<n;i++)
#define foa(e, v) for(auto& e : v)
using ll = long long;
const ll MOD7 = 1000000007, MOD998 = 998244353, INF = (1LL << 61) + (1LL << 60);
#define dout(a) cout<<fixed<<setprecision(10)<<a<<endl;

ll cross(ll x1, ll y1, ll x2, ll y2) {
    // __int128 X1 = x1;
    // __int128 Y1 = y1;
    // __int128 X2 = x2;
    // __int128 Y2 = y2;
    // __int128 inf = INF + 1;
    // return (ll)min(inf, X1 * Y2 - X2 * Y1);
    return x1 * y2 - x2 * y1;
}
using P = pair<ll, ll> ;
vector<P> ConvexHull(vector<ll> x, vector<ll> y) {
    int n = (int)x.size();
    vector<P> res(2*n);
    vector<P> ps;
    rep(i, n) ps.push_back({x[i], y[i]});
    sort(all(ps));
    if(n <= 2) return ps;
    int k = 0;
    for (int i = 0; i < n; ++i) {
        if (k >= 2) {
            while(cross(res[k - 1].first - res[k - 2].first, res[k - 1].second - res[k - 2].second, 
            ps[i].first - res[k - 2].first, ps[i].second - res[k - 2].second) <= 0LL) {
                k --;
                if(k < 2) break;
            }
        }
        res[k] = ps[i]; ++ k;
    }
    int t = k+1;
    for (int i = n-2; i >= 0; --i) {
        if (k >= t) {
            while(cross(res[k - 1].first - res[k - 2].first, res[k - 1].second - res[k - 2].second, 
            ps[i].first - res[k - 2].first, ps[i].second - res[k - 2].second) <= 0LL)  {
                -- k;
                if (k < t) break;
            }
        }
        res[k] = ps[i]; ++k;
    }
    res.resize(k-1);
    return res;
}


void solve() {
    int n;
    cin >> n;
    vector<ll> x(n), y(n);
    map<pair<ll, ll>, ll> mp;
    rep(i, n) {
        cin >> x[i] >> y[i];
        mp[{x[i], y[i]}] = i;
    }
    auto c = ConvexHull(x, y);
    set<int> stc;
    foa(e, c) stc.insert(mp[e]);
    vector<P> in;
    // for(auto [A, B] : c) {
    //     cout << A << " " << B << endl;
    // }
    {
        vector<ll> x1, y1;
        rep(i, n) {
            if(stc.count(i)) continue;
            x1.pb(x[i]);
            y1.pb(y[i]); 
        }
        if(x1.empty()) {
            cout << -1 << endl;
            return;
        }
        in = ConvexHull(x1, y1);
    }
    ll ans = INF;
    int j = 0;
    int m = c.size();
    int sz = in.size();
    auto C = [&](int a, int b) -> ll {
        a %= m;
        a += m;
        a %= m;
        b %= sz;
        b += sz;
        b %= sz;
        int to = (a + 1) % m;
        return abs(cross(c[a].first - in[b].first, c[a].second - in[b].second, c[to].first - in[b].first, c[to].second - in[b].second));
    };
    for(int i = 0; i < m * 2; i ++) {
        ans = min(ans, C(i, j));
        ans = min(ans, C(i, j + 1));
        while(j < sz * 2 + 10 and C(i, j) >= C(i, j + 1)) {
            ans = min(ans, C(i, j));
            ans = min(ans, C(i, j + 1));
            j ++;
        }
        ans = min(ans, C(i, j));
        ans = min(ans, C(i, j + 1));
    }
    j = 0;
    for(int i = 0; i < m * 2; i ++) {
        ans = min(ans, C(i, j));
        ans = min(ans, C(i, j + 1));
        while(j < sz * 2 + 10 and C(i, j) > C(i, j + 1)) {
            ans = min(ans, C(i, j));
            ans = min(ans, C(i, j + 1));
            j ++;
        }
        ans = min(ans, C(i, j));
        ans = min(ans, C(i, j + 1));
    }
    if(sz < 30 or m < 30) {
        for(int i = 0; i < m; i ++) {
            for(j = 0; j < sz; j ++) {
                ans = min(ans, C(i, j));
            }
        }
    }
    ll sum = 0;
    for(int i = 2; i < m; i ++) {
        ll x0 = c[0].first;
        ll y0 = c[0].second;
        ll x1 = c[i - 1].first;
        ll y1 = c[i - 1].second;
        ll x2 = c[i].first;
        ll y2 = c[i].second;
        sum += cross(x1 - x0, y1 - y0, x2 - x0, y2 - y0);
    }
    // assert(sum >= 0);
    // assert(ans >= 0);
    cout << sum - ans << endl;
}
int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int t; cin >> t;
    rep(i, t) solve();
    return 0;
}