#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef vector<pii> vpii;
typedef unsigned long long llu;

#define author ayushtomar
#define rf freopen("in.txt", "r", stdin)
#define wf freopen("out.txt", "w", stdout)
#define debug(x) cerr<<#x<<" "<<x<<endl;
#define f first
#define s second
#define mp make_pair
#define pb push_back
vpii v;
int main()
{
    int t,n;
    cin>>t;
    while(t--)
    {
        v.clear();
        cin>>n;
        int x_min=INT_MAX;
        int x_max=INT_MIN;
        int y_min=INT_MAX;
        int y_max=INT_MIN;
        int flag=0;
        for(int i=1;i<=n;i++)
        {
            int a,b;
            cin>>a>>b;
            v.pb(mp(a,b));
        }
        for(int i=0;i<v.size();i++)
        {
            x_min=min(x_min,v[i].f);
            x_max=max(x_max,v[i].f);
            y_min=min(y_min,v[i].s);
            y_max=max(y_max,v[i].s);
        }
        for(int i=0;i<v.size();i++)
        {
            int a=v[i].f;
            int b=v[i].s;
            if(a==x_min)
            {
                continue;
            }
            else if(a==x_max)
            {
                continue;
            }
            else if(b==y_min)
            {
                continue;
            }
            else if(b==y_max)
            {
                continue;
            }
            flag=1;

        }
        if(flag==1) {cout<<"NO\n";}
        else
            cout<<"YES\n";

    }
    return 0;
}