#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include <set>
using namespace std;
#define lln long long int

int main() {
    lln t;
    cin >> t;
    for(lln i=0;i<t;i++){
        lln n,count=0,maxx=-999999,maxy=-999999,minx=99999,miny=99999;
        cin >> n;
        lln x[n],y[n];
        set <lln> s1,s2;
        for(lln j=0;j<n;j++){
            cin >> x[j] >> y[j];
            if(x[j]>maxx)
                maxx = x[j];
            if(y[j]>maxy)
                maxy = y[j];
            if(x[j]<minx)
                minx = x[j];
            if(y[j]<miny)
                miny = y[j];
            s1.insert(x[j]);
            s2.insert(y[j]);
        }
        for(lln j=0;j<n;j++){
            if(x[j]==maxx || x[j]==minx || y[j]==maxy || y[j]==miny)
                count++;
        }
        if(count==n)
            cout << "YES" << endl;
        else
            cout << "NO" << endl;
    }
    return 0;
}