#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */  
    int q;
    cin>>q;
    for(int i=0;i<q;i++){
        int n;
        vector<int> x,y;
        int temp,temp1;
        cin>>n;
        for(int j=0;j<n;j++){
            cin>>temp>>temp1;
            x.push_back(temp);
            y.push_back(temp1);
        }
        int minx=x[0],maxx=x[0];
        int miny=y[0],maxy=y[0];
        for(int k=1;k<n;k++){
            minx>x[i] ? minx=x[i]:0;
            maxx<x[i] ? maxx=x[i]:0;
            miny>y[i] ? miny=y[i]:0;
            maxy<y[i] ? maxy=y[i]:0;
        }
        bool rec=true;
        for(int k=0;k<n;k++){
            if(x[k]==minx || x[k]==maxx || y[k]==miny || y[k] ==maxy){
                ;
            }else{
                rec=false;
            }
        }
        if(rec){
            cout<<"YES"<<endl;
        }else{
            cout<<"NO"<<endl;
        }
    }
    return 0;
}