#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <limits>
#define INT_MAX 10000
#define INT_MIN -10000
using namespace std;


int main() {
    int t;
    cin>>t;
    while(t--){
        int n;
        cin>>n;
        vector<vector<int> > a(n,vector<int>(2));
        int minx=INT_MAX,maxx=INT_MIN,miny=INT_MAX,maxy=INT_MIN;
        for(int i=0;i<n;i++){
            cin>>a[i][0]>>a[i][1];
            minx = min(minx,a[i][0]);
            maxx = max(maxx,a[i][0]);
            miny = min(miny,a[i][1]);
            maxy = max(maxy,a[i][1]);
        }
        int i;
        for(i=0;i<n;i++){
            if(a[i][0]!=minx&&a[i][1]!=miny&&a[i][0]!=maxx&&a[i][1]!=maxy) break;
        }
        if(i==n) cout<<"YES"<<endl;
        else cout<<"NO"<<endl;
    }
    return 0;
}