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


int main() {
    int q;
    cin>>q;
    while(q--){
        int n, xmax=INT_MIN, xmin=INT_MAX, ymax=INT_MIN, ymin=INT_MAX;
        cin>>n;
        int X[n], Y[n];
        for(int i=0; i<n; i++){
            cin>>X[i]>>Y[i];
            if(i){
            xmin = min(xmin,X[i]);
            ymin = min(ymin,Y[i]);
            xmax = max(xmax,X[i]);
            xmax = max(xmax,X[i]);
            }else{
                xmax= xmin =X[0];
                ymin = ymax = Y[0];
            }
        }
        int f=0;
        for(int i=0; i<n; i++){
            if(!(X[i]==xmin || X[i]==xmax || Y[i]==ymin || Y[i]==ymax)){
                f++;
                break;
            }
        }
        
        if(n>3){
        if(f) cout<<"NO"<<endl;
        else cout<<"YES"<<endl;
        }else cout<<"YES"<<endl;
        
    }
    return 0;
}