#include <cstdio>
#include<bits/stdc++.h>
using namespace std;
int main()
{
    int q;
    cin>>q;
    while(q--)
    {
        vector<long int> vx,vy ;
        long int n;
        long int max_x=-1000000, max_y=-1000000,min_x=1000000,min_y=1000000;
        cin>>n;
        for(int i=0; i<n; i++)
        {
            long int x,y ;
            cin>>x>>y;
            if(x>max_x)
                max_x=x ;
            if (x<min_x)
                min_x=x;
            if (y<min_y)
                min_y=y;
            if(y>max_y)
                max_y=y ;
            vx.push_back(x) ;
            vy.push_back(y) ;
        }
        int i=0;
        for(i=0; i<vx.size(); i++)
        {
            if(vx[i]!=min_x && vy[i]!=min_y && vx[i]!=max_x  && vy[i] !=max_y )
                break ;
        }
        if(i==vx.size())
            cout<<"YES"<<endl;
        else
            cout<<"NO"<<endl;
    }
    return 0;
}