#include <vector>
#include <list>
#include <map>
#include <set>
#include "queue"
#include <deque>
#include <stack>
#include <numeric>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <complex>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cstring>
#include <climits>
#include <cassert>
#include <iostream>
using namespace std;
#define MOD1 1000000007
inline void inp(  int  &n ){n=0;int ch=getchar();int sign=1;while( ch < '0' || ch > '9' ){if(ch=='-')sign=-1; ch=getchar();}while( ch >= '0' && ch <= '9' )n = (n<<3)+(n<<1) + ch-'0', ch=getchar();n=n*sign;}
#define pi acos(-1)
#define For(i,a,b) for(int i=a;i<=b;i++)
#define pii pair<long long ,long long >
#define vii vector<pii>
#define ll  long long int
#define loop(i,n) for(ll i=0;i<n;i++)
#define loop2(i,n) for(ll i=1;i<=n;i++)
#define pb push_back
#define mp make_pair
#define OUT_RT cerr << (float(clock()) / CLOCKS_PER_SEC) << endl
#define display(x) for(ll  i = 0 ;i<x.size();i+=1){cout<<x[i]<<" ";} cout<<endl;
#define displayarr(x,n) loop(i,n){cout<<x[i]<<" ";}cout<<endl;
#define EPS 1e-9
using namespace std;

//Code till the end of the contest
//JAI SHREE KRISHNA




int main()
{
    
    ios::sync_with_stdio(false);
    cin.tie(0);
    
    ll q;
    cin>>q;
    while (q--) {
        ll n;
        cin>>n;
        vector<pii>v1;
        ll minx = (ll)1e18;
        ll maxx = -(ll)1e18;
        ll maxy = -(ll)1e18;
        ll miny = (ll)1e18;
        loop(i,n)
        {
            ll a,b;
            cin>>a>>b;
            v1.pb(mp(a,b));
            minx = min(minx,a);
            maxx = max(maxx,a);
            maxy = max(maxy,b);
            miny = min(miny,b);
        }
        
        bool arr[n];
        loop(i,n)
        {
            arr[i] = false;
        }
        loop(i,v1.size())
        {
            if((v1[i].first==minx||v1[i].first==maxx))
            {
                if(v1[i].second>=miny&&v1[i].second<=maxy)
                {
                    arr[i] = true;
                }
            }
            if(v1[i].second==miny||v1[i].second==maxy)
            {
                if(v1[i].first>=minx&&v1[i].first<=maxx)
                {
                    arr[i] = true;
                }
            }
        }
        bool cool = true;
        loop(i,n)
        {
            cool&=arr[i];
        }
        if(cool)
        {
            cout<<"YES\n";
        }
        else{
            cout<<"NO\n";
        }
    }
    return 0;
    
}