#include<bits/stdc++.h>
using namespace std;
#define mod 1000000007LL
#define ll long long
#define ii pair<ll,int>
#define vi vector<int>

int main()
{
	ll q;
	cin >> q;
	while(q--)
	{
		ll a[11],b[11];
		ll n;
        ll minx = mod,miny = mod,maxx = -mod,maxy = -mod;
		cin >> n;
		ll flag = 1;
		for(ll i =0; i < n; i++)
		{
		 	cin >> a[i] >> b[i];
		 	minx=min(minx,a[i]);
		 	maxx=max(maxx,a[i]);
		 	miny=min(miny,b[i]);
		 	maxy=max(maxy,b[i]);
		}

        for(ll i = 0; i < n; i++)
        {
            if( (a[i] != minx) && (a[i] != maxx) && (b[i] != miny) && (b[i] != maxy))
            {
            	flag = 0;
            	break;
            }
            
        }
		if(flag)
			cout << "YES\n";
		else
			cout << "NO\n";
	}
	return 0;
}