#include <bits/stdc++.h>
 using namespace std;

#define fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define LL long long int
#define pb push_back 
#define mp make_pair
#define PII pair<int,int>
#define test int t;cin>>t;while(t--)
#define ff first
#define ss second
#define input(a,n) for(i=0;i<n;i++)cin>>a[i];

 
int main() {
    fast
    LL n,b,i,j,k,z,x=0,y=0,sum=1e18,p,q,r,sl,T,m,ans=0,s;
    double xx,yy;
   
 
    int qq;
     cin>>qq;
      bool f[10],g;
     while(qq--)
     {
     	cin>>n;
     	vector<PII > v;
         r=p=10000000;
         s=q=-10000000;
     	for(i=0;i<n;i++)
     	{
     		cin>>x>>y;
            v.pb(mp(x,y));
     	    p=min(x,p);
            q=max(x,q);
            r=min(r,y);
            s=max(s,y);
     	}
     	     	
         for(i=0;i<n;i++)
           {
             x=v[i].ff;
             y=v[i].ss;
             if(x!=p && x!=q && y!=r && y!=s)
               break;
         }
         if(i==n)
             cout<<"YES\n";
         else
             cout<<"NO\n";

     	
 }
     
     return 0;
}