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


int main() {
    int l;
cin>>l;
while(l--){
int n,m,q,i=0,j=0,possmaxx=-32627,negminx=32627;
int possmaxy=-32627;
int negminy=32627;
cin>>q;
int a[100000],b[100000];
while(q--){
cin>>a[i]>>b[j];
if(possmaxx<a[i]){
possmaxx=a[i];
}
if(negminx>a[i]){
negminx=a[i];
}
if(possmaxy<b[j]){
possmaxy=b[j];
}
if(negminy>b[j]){
negminy=b[j];
}
i++;
j++;
}
    int flag1=1,flag2=1,x,y;
while(i--){
if(a[i]==possmaxx||a[i]==negminx||b[i]==possmaxy||b[i]==negminy)
flag1=1;
else
{
flag1=0;
break;
}

}

if(flag1==1){
cout<<"YES"<<endl;
}
    else
        {
        cout<<"NO"<<endl;
    }

}
    return 0;
}