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


int main() {
    int t;
    cin >> t;
    while(t--){
        int n;
        cin >> n;
        vector<int> xs, ys;
        int minx, maxx, miny, maxy;
        int x, y;
        cin >> x >> y;
        minx = x;
        maxx = x;
        miny = y;
        maxy = y;
        n--;
        xs.push_back(x);
        ys.push_back(y);
        while(n--){
            cin >> x >> y;
            minx = min(minx, x);
            maxx = max(maxx, x);
            miny = min(miny, y);
            maxy = max(maxy, y);
            xs.push_back(x);
            ys.push_back(y);
        }
        
        bool good=true;
        for(int i = 0; i<xs.size(); ++i){
            int x = xs[i];
            int y = ys[i];
            
            if (x > minx && x < maxx && y > miny && y < maxy){
                good = false;
                break;
            }
        }
        
        if (good){
            cout << "YES" << endl;
        }
        else {
            cout << "NO" << endl;
        }
    }
    return 0;
}