#include <bits/stdc++.h>
using namespace std;
#define forn(i, n) for (int i = 0; i < (int)(n); ++i)
#define fore(i, b, e) for (int i = (int)(b); i <= (int)(e); ++i)
#define ford(i, n) for (int i = (int)(n) - 1; i >= 0; --i)
#define pb push_back
#define fi first
#define se second
#define all(x) (x).begin(), (x).end()
typedef vector<int> vi;
typedef pair<int, int> pii;
typedef long long i64;
typedef unsigned long long u64;
typedef long double ld;
typedef long long ll;
// #define sz(x) int((x).size())
const int inf = 1e9;

int x[100], y[100];

int main() {
#ifdef LOCAL
    freopen("b.in", "r", stdin);
#endif

    int q;
    cin >> q;
    forn(I, q) {
        int n;
        cin >> n;
        int mxx = -inf, mnx = inf;
        int mxy = -inf, mny = inf;
        forn(i, n) {
            cin >> x[i] >> y[i];
            mxx = max(mxx, x[i]);
            mnx = min(mnx, x[i]);
            mxy = max(mxy, y[i]);
            mny = min(mny, y[i]);
        }

        if (mxx == mnx) ++mxx;
        if (mxy == mny) ++mxy;
        bool fail = false;
        forn(i, n) {
            if (x[i] != mnx && x[i] != mxx && y[i] != mny && y[i] != mxy) {
                fail = true;
            }
        }
        cout << (fail ? "NO" : "YES") << endl;
    }

#ifdef LOCAL
    cerr << "Time elapsed: " << clock() / 1000 << " ms" << endl;
#endif
    return 0;
}