#include <iostream>
#include <fstream>
#include <vector>
#include <stack>
#include <algorithm>
#include <queue>
#include <string>
#include <cmath>
#include <map>
#include <set>
#include <cassert>
#define MOD 1e9 + 7
#define eps 1e-9
#define pb push_back
#define mp make_pair
#define ft first
#define sd second
#define sz(a) a.size()
#define loop(i, n) for(long long (i) = 0; (i) < (n) ; ++ (i))
#define loopn()
#define pii pair<int,int>
#define pll pair<long long,long long>
#define pld pair<long double, long double>
#define vii vector<int>
#define vll vector<long long>  
typedef long long ll;
typedef long double ld;

using namespace std;


/*@Sergey_Miller*/


ll f(ll n, ll m) {
    if(n == 1) {
        return m-1;
    }
    if(m == 1) {
        return n-1;
    }
    if(n < m) {
        swap(n,m);
    }
    ll ans = n;
    if(m%2 == 0) {
        return 1 + 2*f(n,m/2);
    } else {
        return 1 + f(n,m/2) + f(n,m/2  +1);
    }
}


void solve() {
    ll q;
    cin >> q;
    loop(t,q) {
        ll n;
        cin >> n;
        vector <pll> v(n);
        loop(i,n) {
            cin >> v[i].ft >> v[i].sd;
        }
        ll minx = 1e5, maxx = -1e5, miny = 1e5, maxy = -1e5;
        loop(i,n) {
            minx = min(minx, v[i].ft);
            maxx = max(maxx, v[i].ft);
            miny = min(miny, v[i].sd);
            maxy = max(maxy, v[i].sd);
        }
        // if(maxx == minx || miny == maxy) {
        //     cout << "NO" << endl;
        //     continue;
        // }

        ll er = 0;
        loop(i,n) {
            if((v[i].ft != maxx && v[i].ft != minx) && (v[i].sd != miny && v[i].sd != maxy)) {
                er = 1;
            break;
            }
        }
        if(er) {
            cout << "NO" << endl;
            continue;
        }
        cout << "YES" << endl;
    }
}

int main () {
    ios::sync_with_stdio(false);
     // freopen("input.txt", "r", stdin);
 //  freopen("output.txt", "w", stdout);
    solve();
    return 0;
}