#include<iostream>
#include<unordered_map>
using namespace std;

int main()
{
  
    long long a,b,x[100005],y[100005],mix=1000000007,miy=1000000007,mxx=-1000000007,mxy=-1000000007,n,i,flag=0,t;
    cin>>t;
    while(t--)
    {
        mix=1000000007;miy=1000000007;mxx=-1000000007;mxy=-1000000007;flag=0;
    cin>>n;
    for(i=0;i<n;i++)
    {
        cin>>x[i]>>y[i];
        mix=min(mix,x[i]);
        mxx=max(mxx,x[i]);
        miy=min(miy,y[i]);
        mxy=max(mxy,y[i]);
    }
     for(i=0;i<n;i++)
     {
         if(!((x[i]==mix||x[i]==mxx)||(y[i]==miy||y[i]==mxy)))
         {
             flag=1;
             break;
         }
     }
        if(flag)
            cout<<"NO"<<endl;
        else
            cout<<"YES"<<endl;
    }
}