#include<bits/stdc++.h>
using namespace std;
int xc[51],yc[51];
pair<int,int> pp[51];

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */ 
    
    int q;
    cin>>q;
   
    int x,y;
    
    while(q--)
        {
        int n;
        cin>>n;
        
       
        
        for(int i=0;i<n;i++)
            {
            cin>>xc[i];
            cin>>yc[i];
            
            pp[i]=make_pair(xc[i],yc[i]);
            
        }

        
        sort(xc,xc+n);
        sort(yc,yc+n);
        
        int m1x=xc[0],m2x=xc[n-1];
        int m1y=yc[0],m2y=yc[n-1];
        
        int i;
        
        for(i=0;i<n;i++)
            {
            int ox=pp[i].first;
            int oy=pp[i].second;
            
            if((ox==m1x || ox==m2x) || (oy==m1y || oy==m2y));
            else
                break;
        }
        
        
        
        if(i==n)
            cout<<"YES\n";
        else
            cout<<"NO\n";
    }
    return 0;
}