#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 l;
    cin>>l;
    while(l--){
   int n,m,q,i=0,j=0,possmaxx=-32627,negminx=32627;
    int possmaxy=-32627;
    int  negminy=32627;
    cin>>q;
    int a[100000],b[100000];
    while(q--){
         cin>>a[i]>>b[j];
        //cout<<a[i]<<b[j]<<endl;
        
        
      
             if(possmaxx<a[i]){
                 possmaxx=a[i];
             }
           
         
      
                 if(negminx>a[i]){
                     negminx=a[i];
                 }
                
             
             
            
         
   
             if(possmaxy<b[j]){
                 possmaxy=b[j];
             }
             
         
                 if(negminy>b[j]){
                     negminy=b[j];
                 }
                 
             
             
            i++;
            j++;
         
    
    
    }
        //cout<<i<<j;
        int flag1=1,flag2=1,x,y;
        while(i--){
          if(a[i]==possmaxx||a[i]==negminx||b[i]==possmaxy||b[i]==negminy)
                flag1=1;
            else
                {
                flag1=0;
                break;
            }
             
        }
       /* for(x=0;x<i;x++){
            cout<<x<<endl;
            if(a[x]==possmaxx&&a[x]==negminx)
                flag1=1;
            else
                {
                flag1=0;
                break;
            }
        }
        for(y=0;y<j;y++){
           // cout<<b[m1];
            if(b[y]==possmaxy&&b[y]==negminy)
                flag2=1;
            else
                {
                flag2=0;
                break;
            }
            
        }
        */
       if(flag1==1){
           cout<<"YES"<<endl;
       }
        else
            {
            cout<<"NO"<<endl;
        }
  //  cout<<possmaxx<<" "<<negminx<<endl;
    
   // cout<<possmaxy<<" "<<negminy<<endl;
    }
    return 0;
}