#include <iostream>
#include <algorithm>
#include <map>
#include <vector>
#include <set>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<int,int> pii;
#define Boost ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
#define pb push_back
#define mp make_pair

const int inf = 2147483647;
const int MOD = 1e9+7;
const int MAXN = 1e5+9;

int main() {
//    Boost;
    int t;
    cin>>t;
    while(t--){
        int n;
        cin>>n;
        ll x[n],y[n];
        ll minx=inf,miny=inf,maxx=-inf,maxy=-inf;
        for (int i = 0; i < n; ++i) {
            cin>>x[i]>>y[i];
            minx = min(minx, x[i]);
            maxx = max(maxx, x[i]);
            miny = min(miny, y[i]);
            maxy = max(maxy, y[i]);
        }
        if(n<3)
            cout<<"YES"<<"\n";
        else{
            int flag=1;
            for (int i = 0; i < n; ++i) {
                if((x[i]!=minx && x[i]!=maxx) && (y[i]!=miny && y[i]!=maxy))
                    flag=0;
            }
            if(flag==1)
                cout<<"YES"<<"\n";
            else
                cout<<"NO"<<"\n";
        }
    }
    return 0;
}