#include <algorithm>
#include <bitset>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;

#define	loo(i,a,b)	for(auto i=a;i<b;i++)
#define	rep(i,b)	loo(i,0,b)
#define dow(i,b)	for(auto i=b-1;i>=0;i--)

#define sz(a)		((int)(a.size()))
#define all(a)		a.begin(),a.end()
#define in(a,e)		((a).find(e)!=(a).end())

typedef unsigned int ui;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<ui> vui;
typedef vector<ll> vll;
typedef vector<ull> vull;
typedef vector<vi> vvi;
typedef vector<ii> vii;
typedef unordered_set<int> unsi;
typedef unordered_map<int,int> unmii;
typedef long double ld;
using graph = vector<vector<pair<int,int>>>;

const int mv4[4][2] = { { 0,1 },{ 0,-1 },{ 1,0 },{ -1,0 } };
const int mv8[8][2] = { { 0,1 },{ 0,-1 },{ 1,0 },{ -1,0 },{ 1,1 },{ 1,-1 },{ -1,1 },{ -1,-1 } };
const int inf = (int)1e9;
const char *boo[2] = { "NO","YES" };
const char *inv = "Impossible";
inline void term(const string &msg = inv) { cout << msg << endl; exit(0); }

const char *fin = "in.txt";
const char *fout = "out.txt";

#define SUBMIT	//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

int main() {
#ifndef SUBMIT
	freopen(fin, "r", stdin);
	freopen(fout, "w", stdout);
#endif
	cin.sync_with_stdio(0);
	cout.sync_with_stdio(0);

	int q,n;
	cin >> q;
    rep(i,q){
        cin>>n;
        vi x(n),y(n);
        rep(i, n){
            cin >> x[i]>>y[i];
        }
        auto x1=*min_element(all(x));
        auto x2=*max_element(all(x));
        auto y1=*min_element(all(y));
        auto y2=*max_element(all(y));
        bool flag=1;
        rep(i,n){
            if(
                !(x[i]==x1 || x[i]==x2 || y[i]==y1 ||y[i]==y2)
            ){
                flag=0;
                break;
            }
        }
        
        cout << boo[flag] << endl;
    }
	exit(0);
}