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


int main() {
    int q;
    cin>>q;
    while(q--)
        {
        int n;
        cin>>n;
        int maxx=INT_MIN,maxy=INT_MIN,minx=INT_MAX,miny=INT_MAX;
        int a[n],b[n];
        for(int i=0;i<n;i++)
            {
             cin>>a[i];
             cin>>b[i];
             if(a[i]>maxx)
                 maxx = a[i];
            if(a[i]<minx)
                minx = a[i];
            if(b[i]>maxy)
                maxy=b[i];
            if(b[i]<miny)
                miny = b[i];
            
        }
        int flag= 0;
        for(int i=0;i<n;i++)
            {
            if((a[i]<maxx && a[i]>minx) && (b[i]> miny && b[i]< maxy))
               {
                  flag =1; 
               }
        }
    
               if(flag==1)
               cout<<"NO\n";
               else
               cout<<"YES\n";
               }
    return 0;
}