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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int t;
    cin>>t;
    while(t--)
    {   int n,a[15][2];
        cin>>n;
     int minx,miny,maxy,maxx;
     minx=miny=INT_MAX;maxx=maxy=INT_MIN;
        for(int i=0;i<n;i++)
         {     cin>>a[i][0]>>a[i][1];
                if(a[i][0]<minx)
                     minx=a[i][0];
                if(a[i][0]>maxx)
                     maxx=a[i][0];
                if(a[i][1]<miny)
                     miny=a[i][1];
                if(a[i][1]>maxy)
                     maxy=a[i][1];
         }
        
        
        int f=1;
        for(int i=0;i<n;i++)
        {
            if(!(a[i][0]==minx || a[i][0]==maxx || a[i][1]==miny || a[i][1]==maxy))
            {
                f=0;break;
            }
        }
     if(f)
         cout<<"YES\n";
     else
         cout<<"NO\n";
        
    }
    return 0;
}