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

int cmp(pair<int,int>a,pair<int,int>b)
{
    return a.second<b.second;
}
int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */  
    int q,n,x,y;
    cin>>q;
    while(q--){
        cin>>n;
        int ax[n],ay[n];
        for(int i=0;i<n;i++)
           cin>>ax[i]>>ay[i];
        int x1=1000004,x2=-1000004,y1=1000004,y2=-1000004;
        for(int i=0;i<n;i++)
            {
            if(x1>ax[i]) x1 = ax[i];
            if(x2<ax[i]) x2 = ax[i];
            if(y1>ay[i]) y1 = ay[i];
            if(y2<ay[i]) y2 = ay[i];
           }
            bool flag=true;
            for(int i=0; i<n; i++){
                if (ay[i]==y2 || ay[i]==y1){
                    continue;
                }
                if (ax[i]==x1 || ax[i]==x2){
                    continue;
                    
                }
                flag=false;
                break;
            }
        cout<<(flag?"YES":"NO")<<endl;
    }
    return 0;
}