#include <iostream>
#include <string>
#include <stdio.h>
#include <fstream>
#include <algorithm>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <cmath>
#include <cassert>
using namespace std;
typedef long long ll;
typedef long double ld;
#define PI (ld)3.14159265358979324
#define mp make_pair 
#define pb push_back
#define ft first
// #define sd second
#define sz(a) (ll)a.size()
#define pii pair<int,int>
#define pll pair<ll,ll>
#define loop(i, n) for(int (i) = 0; (i) < (n) ; ++ (i))
#define forn(i, l, r) for(int (i) = (l); (i) < (r) ; ++ (i))
#define vec vector 
#define str string
/*******************************************************/


void solve() {
    int n;
    cin >> n;
    vec<pii> pt(n);
    loop(i,n) cin >> pt[i].first >> pt[i].second;
    if(n <= 2) {
        cout << "YES";
        return;
    }

    int minx=pt[0].first,maxx=pt[0].first,miny=pt[0].second,maxy=pt[0].second;
    loop(i,n) {
        maxx = max(maxx,pt[i].first);
        minx = min(minx,pt[i].first);
        maxy = max(maxy,pt[i].second);
        miny = min(miny,pt[i].second);
    }

    loop(i,n) {
        int x = pt[i].first;
        int y = pt[i].second;
        if(x != maxx && x != minx && y != maxy && y != miny) {
            cout << "NO";
            return;
        }
    }
    cout <<"YES";

}


int main()
{
    // freopen("in.txt","r", stdin);
    ios_base::sync_with_stdio(false);   
    // cout << fixed;
    // cout.precision(3);

    int q ;
    cin >> q;
    loop(i,q){
        solve();
        cout <<endl;
    }
    return 0;
}