#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */ 
    int t,n,xma,xmi,yma,ymi,f;
    cin>>t;
    while(t)
        {
        f=0;
        cin>>n;
        int a[n],b[n];
        for(int i=0;i<n;i++){
            cin>>a[i]>>b[i];
            if(i==0)
               {xma=xmi=a[0];
                yma=ymi=b[0];
               }
            if(a[i]>xma)
                xma=a[i];
            if(a[i]<xmi)
                xmi=a[i];
            if(b[i]<ymi)
                ymi=b[i];
            if(b[i]>yma)
                yma=b[i];
        }
        for(int i=0;i<n;i++)
            {
              if(a[i]>xmi&&a[i]<xma&&b[i]<yma&&b[i]>ymi)
              {f=1;
               break;}            
            }
           if(f==0)
               cout<<"YES"<<endl;
            else
                cout<<"NO"<<endl;
            
        
        t--;
    }
    return 0;
}