#include <bits/stdc++.h>
#define ll long long int
#define PB push_back
#define ld long double
#define MP make_pair
#define F first
#define S second
#define sd(x) scanf("%d",&x)

using namespace std;


int main() {
     ll q;
    cin>>q;
    while(q--){
        ll n;
        cin>>n;
        vector<pair<ll,ll> > v(n,MP(0,0));
        ll minx = INT_MAX;
        ll miny = INT_MAX;
        ll maxx = INT_MIN;
        ll maxy = INT_MIN;
        for(int i = 0;i<n;i++){
            cin>>v[i].F;
            cin>>v[i].S;
            minx = min(minx,v[i].F);
            miny = min(miny,v[i].S);
            maxx = max(maxx ,v[i].F);
            maxy = max(maxy,v[i].S);
        }
        bool ch = true;
        for(int i = 0;i<n;i++){
            if(v[i].S != miny && v[i].S != maxy && v[i].F != minx && v[i].F!=maxx){
                ch = false;
                break;
            }
        }
        if(ch)cout<<"YES"<<endl;
        else cout<<"NO"<<endl;
        
    }
    return 0;
}