#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;
    set<int> si,sj;
    while(t--){
        int n;
        cin>>n;
        int ar[n+2][2];
        
        for(int ii=0;ii<n;++ii){
            int i,j;
            cin>>i>>j;
            ar[ii][0]=i;
            ar[ii][1]=j;
        }
        int mini=ar[0][0],minj=ar[0][1],maxi=ar[0][0],maxj=ar[0][1];
        for(int ii=1;ii<n;++ii){
               mini=mini<ar[ii][0]?mini:ar[ii][0];
               maxi=maxi>ar[ii][0]?maxi:ar[ii][0];
               minj=minj<ar[ii][1]?minj:ar[ii][1];
               maxj=maxj>ar[ii][1]?maxj:ar[ii][1];
        }
        int flag=-1;
        for(int ii=0;ii<n;++ii){
         if(ar[ii][0]==mini || ar[ii][0]==maxi || ar[ii][1]==maxj || ar[ii][1]==minj)continue;
           flag=1;
            break;
        }
        if(flag==1)cout<<"NO"<<endl;
        else cout<<"YES"<<endl;
        
       
    }
    return 0;
}