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


int main() {
    int q;
    cin >> q;
    int size = 20001;
    while(q--){
        int n;
        cin >> n;
        //cout << n;
        vector<pair<int,int> > A;
        int xmin = 100000,xmax = -100000,ymin = 100000,ymax = -100000;
        bool flag = 1;
        for(int i=0;i<n;i++){
            int u,v;
            cin >> u >> v;
            A.push_back(make_pair(u,v));
            xmin = min(xmin,u);
            xmax = max(xmax,u);
            ymin = min(ymin,v);
            ymax = max(ymax,v);
        }
        //cout << xmin << xmax << ymin << ymax << " ";
        for(int i=0;i<n;i++){
            int u = A[i].first,v = A[i].second;
            if(!(u == xmin || u == xmax || v == ymin || v == ymax)) {
                flag = 0;
                break;
            }
        }
        if(flag) cout << "YES" << endl;
        else cout << "NO" << endl;
    }
    return 0;
}