#include<bits/stdc++.h>
#define MAXN 211111
using namespace std;
#define ff first
#define ss second
int q,n;
pair<int,int>a[MAXN];


int main(){

    //freopen("in.txt","r",stdin);
    cin>>q;
    while(q--){
        cin>>n;
        for(int i = 0 ; i < n;i++ ) {
            cin>>a[i].ff>>a[i].ss;
        }

        int mnx = a[0].ff;
        int mxx = a[0].ff;
        int mny = a[0].ss;
        int mxy = a[0].ss;

        for(int i = 0 ; i < n;i++){
            mnx = min(mnx, a[i].ff);
            mxx = max(mxx, a[i].ff);

            mny = min(mny, a[i].ss);
            mxy = max(mxy, a[i].ss);
        }
        bool f1=1;
        for(int  i= 0 ;i < n;i++){
            if(a[i].ff==mnx || a[i].ff==mxx || a[i].ss==mny || a[i].ss ==mxy){

            }
            else {
                f1=0;
            }
        }
        
        if(f1){
            cout<<"YES\n";
        }
        else{
            cout<<"NO\n";
        }
    }
    return 0;
}