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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int q;
    cin>>q;
    while(q--)
    {
        int n;
        cin>>n;
        vector<int> x,y;
        int min1=INT_MAX,min2=INT_MAX;
        int max1 = INT_MIN,max2=INT_MIN;
        for(int i=0;i<n;i++)
        {
            int x1,y1;
            cin>>x1>>y1;
            x.push_back(x1);
            y.push_back(y1);
            min1 = min(min1,x1);
            min2 = min(min2,y1);
            max1 = max(max1,x1);
            max2 = max(max2,y1);
            
        }
        int k=0;
        for(int i=0;i<n;i++)
        {
            if(x[i]!=min1 && x[i]!=max1&&y[i]!=min2 && y[i]!=max2) {
                cout<<"NO"<<endl;
                k=1;
                break;
            }
        }
        if(k==0)
            cout<<"YES"<<endl;
    }
    return 0;
}