#include <cmath>
#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 */   
    long long int t,n,i;
    cin>>t;
    while(t--)
        {
        cin>>n;
        long long int x[n],y[n];
        for(i=0;i<n;++i)
            cin>>x[i]>>y[i];
        long long int max_x=x[0],max_y=y[0],min_x=x[0],min_y=y[0];
        for(i=1;i<n;++i)
            {
            if(x[i]>max_x)
                max_x=x[i];
            if(x[i]<min_x)
                min_x=x[i];
            if(y[i]>max_y)
                max_y=y[i];
            if(y[i]<min_y)
                min_y=y[i];
        }
        int flag=1;
        for(i=0;i<n;++i)
            {
            if(x[i]==max_x || x[i]==min_x || y[i]==min_y || y[i]==max_y)
                continue;
            else 
                {
                flag=0;
                break;
            }
        }
        if(flag==0)
            cout<<"NO\n";
        else cout<<"YES\n";
    }
    return 0;
}