#include <bits/stdc++.h>

using namespace std;


int main() {
    int q,n,i,largex,largey,minx,miny;
    cin>>q;
    while(q--)
        { largex=INT_MIN;
         largey=INT_MIN;
         minx=INT_MAX;
         miny=INT_MAX;
        cin>>n;
       int x[n],y[n];
        for(i=0;i<n;i++)
           { cin>>x[i]>>y[i];
            if(largex<x[i])
                largex=x[i];
            if(minx>x[i])
                minx=x[i];
            if(largey<y[i])
                largey=y[i];
            if(miny>y[i])
                miny=y[i];
            
        
        }
       for(i=0;i<n;i++)
           {
           if(x[i]!=largex&&y[i]!=largex&&x[i]!=minx&&y[i]!=miny)
               break;
          else continue;
         }
         if(i==n)
             cout<<"YES\n";
         else cout<<"NO\n";
    }
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}