#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
typedef long long int ll;

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */ 
    ll t;
    cin>>t;
    while(t--)
        {
        ll n,i,j,p=0,m,q=0,r;
        cin>>n;
        ll a[n],b[n];
        for(i=0;i<n;i++)
            cin>>a[i]>>b[i];
        ll min1=*min_element(a,a+n);
        ll min2=*min_element(b,b+n);
        ll max1=*max_element(a,a+n);
        ll max2=*max_element(b,b+n);
        for(i=0;i<n;i++)
            {
            if(a[i]==min1||a[i]==max1)
                {
                if(b[i]>max2)
                    {q=1;break;}
            }
            else if(b[i]==min2||b[i]==max2)
                {
                if(a[i]>max1)
                    {q=1;break;}
            }
            else {q=1;break;}
        }
        if(q==1)
            cout<<"NO"<<endl;
        else cout<<"YES"<<endl;
    }    return 0;
}