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

#define sz 100
int q, n, pointX[sz], pointY[sz];
int lowestX = 0;
int highestX = 0;
int lowestY = 0;
int highestY = 0;

bool isOnRectange(int x, int y){
    
    if ( !(x >= lowestX && x <= highestX)) return false;
    if ( !(y >= lowestY && y <= highestY)) return false;
    
    //cout << x << " " << " " << lowestX  << " " << highestX << endl;
    if (x == lowestX || x == highestX) return true;
    if (y == lowestY || y == highestY) return true;
    
    return false;
}

int main() {
    
    
    
    cin >> q;
    
    
    while (q--){
        cin >> n;
        
        for (int i=0;i<n;i++){
            cin >> pointX[i] >> pointY[i];
        }
        
        lowestX = pointX[0];
        highestX = pointX[0];
        lowestY = pointY[0];
        highestY = pointY[0];
        
        for (int i=1;i<n;i++){
            if (pointX[i] < lowestX) lowestX = pointX[i];
            if (pointX[i] > highestX) highestX = pointX[i];
            if (pointY[i] < lowestY) lowestY = pointY[i];
            if (pointY[i] > highestY) highestY = pointY[i];
        }
        /*
        cout << lowestX << "," << lowestY << endl;
        cout << highestX << "," << lowestY << endl;
        cout << lowestX << "," << highestY << endl;
        cout << highestX << "," << highestY << endl;
        */
        bool yes  = true;
        
        
        for (int i=0;i<n;i++){
            yes = isOnRectange(pointX[i], pointY[i]);
            if (! yes) {
                //cout << "  ss "  << pointX[i] << " " << pointY[i] << endl;
                break;
            }
        }
            
        
        if (yes) cout << "YES" << endl;
        else cout << "NO" << endl;
        
        
        
    }
    
    return 0;
}