#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,n;
    cin>>q;
    while(q--){
        cin>>n;
        int flag=0;
        int x[n],y[n];
        int xmax=-100100,xmin=100010,ymin=100010,ymax=-100100;
        for(int i=0;i<n;i++){
            cin>>x[i]>>y[i];
            if(xmax<x[i])xmax=x[i];
            if(xmin>x[i])xmin=x[i];
            if(ymax<y[i])ymax=y[i];
            if(ymin>y[i])ymin=y[i];
        }
        for(int i=0;i<n;i++){
            if(x[i]==xmax||x[i]==xmin||y[i]==ymin||y[i]==ymax)continue;
            else{
                flag=1;
                break;
            }
        }
        if(flag==1)cout<<"NO"<<endl;
        else cout<<"YES"<<endl;
        
    }
    return 0;
}