#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 */  
    int q,j;
    cin>>q;
    for(j=0;j<q;j++)
        {
        int n,i,flag=0;
        cin>>n;
        int x[n],y[n];
        int maxx=-10001,maxy=-10001;
        int minx=100001,miny=-10001;
        for(i=0;i<n;i++)
            {
            cin>>x[i]>>y[i];
            if(x[i]>maxx)
                maxx=x[i];
            if(x[i]<minx)
                minx=x[i];
            if(maxy>y[i])
                maxy=y[i];
            if(miny>y[i])
                miny=y[i];
        }
        for(i=0;i<n;i++)
            {
            if(x[i]==minx||x[i]==maxx)
                flag=1;
            else if(y[i]==miny||y[i]==maxy)
                flag=1;
                else{
                flag=0;
                break;
            }
        }
        if(flag==0)
            cout<<"NO"<<endl;
        else
            cout<<"YES"<<endl;
    }
    return 0;
}