#include<bits/stdc++.h>
using namespace std;
#define ll long long
int main()
{
    ll n,m,t,i,ans,q;
    cin>>q;
    while(q--){
        cin>>n;
        ll x[n+1],y[n+1];
        ll xmax,ymax,xmin,ymin;
        ymax=xmax=-100005;
        ymin=xmin=100005;
        for(i=0;i<n;i++){
            cin>>x[i]>>y[i];
            xmax=max(xmax,x[i]);
            xmin=min(xmin,x[i]);
            ymax=max(ymax,y[i]);
            ymin=min(ymin,y[i]);
        }
        ll cnt=0;
        for(i=0;i<n;i++){
            if(x[i]>=xmin && x[i]<=xmax && y[i]>=ymin && y[i]<=ymax){
                if(x[i]==xmax || x[i]==xmin || y[i]==ymax || y[i]==ymin){
                    cnt++;
                }
            }
        }
        if(cnt==n)
            cout<<"YES\n";
        else
            cout<<"NO\n";
    }
    return 0;
}