#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)
#define ll long long
#define pi pair<ll, ll>
#define pii pair<pi,ll>
#define pb push_back
#define F first
#define S second
#define mod 1000000007
#define maxn 10005
#define boost ios::sync_with_stdio(false);cin.tie(0)
#define fr freopen("source.txt","r",stdin),freopen("output.txt","w",stdout)
pi p[15];
int main(){
    boost;
    
    int q;
    cin>>q;
    while(q--){
        int n;
        cin>>n;
        ll mx=maxn;
        ll my=maxn;
        ll Mx=-maxn;
        ll My=-maxn;
        for(int i=1;i<=n;i++)cin>>p[i].F>>p[i].S;
        for(int i=1;i<=n;i++)mx=min(mx,p[i].F);
        for(int i=1;i<=n;i++)my=min(my,p[i].S);
        for(int i=1;i<=n;i++)Mx=max(Mx,p[i].F);
        for(int i=1;i<=n;i++)My=max(My,p[i].S);
        
        int f=1;
        for(int i=1;i<=n;i++){
            if(p[i].F!=mx&&p[i].F!=Mx&&p[i].S!=my&&p[i].S!=My){
                f=0;
                break;
            }
        }
        cout<<(f?"YES\n":"NO\n");
    }

    return 0;
}