#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

typedef pair<int, int> pii;

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int q, n, i, j;
    cin>>q;
    while(q--) {
        cin>>n;
        int x, y;
        vector<pii> v;
        int maxx=-100000, minx=100000;
        int maxy=maxx, miny=minx;
        for(i=1; i<=n; ++i) {
            cin>>x>>y;
            maxx=max(x, maxx);
            minx=min(x, minx);
            miny=min(y, miny);
            maxy=max(y, maxy);
            v.push_back({x, y});
        }
        bool flag=true;
        for(i=0; i<v.size(); ++i) {
            if(v[i].first!=minx && v[i].first!=maxx && v[i].second!=miny && v[i].second!=maxy) {
                flag=false;
                //cout<<i<<endl;
                break;
            }
        }
        if(flag)    cout<<"YES\n";
        else    cout<<"NO\n";
    }
    return 0;
}