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

typedef long long int ll;

#define pb push_back
#define mp make_pair
#define fi first
#define se second

void init()
{
    int q,n,x,y,i;
    cin >> q;
    while(q--)
    {
        vector<int> X,Y;
        cin >> n;
        for(i=0;i<n;i++)
        {
            cin >> x >> y ;
            X.pb(x);
            Y.pb(y);
        }
        if(n==1 || n==2)
        cout << "YES\n";
        else
        {
            //sort(X.begin(),X.end());
            //sort(Y.begin(),Y.end());
            int x1=*min_element(X.begin(),X.end());
            int x2=*max_element(X.begin(),X.end());
            int y1=*min_element(Y.begin(),Y.end());
            int y2=*max_element(Y.begin(),Y.end());
            if(x1==x2 || y1==y2)
            cout << "YES\n";
            else
            {
                /*int x1=X[0];
                int x2=X[n-1];
                int y1=Y[0];
                int y2=Y[n-1];*/
                int flag=0;
                for(i=0;i<n;i++)
                {
                    if(X[i]<x2 && X[i]>x1 && Y[i]<y2 && Y[i]>y1)
                    {
                        flag=1;
                        break;
                    }
                }
                if(flag==1)
                cout << "NO\n";
                else
                cout << "YES\n";
            }
        }

    }
}

int main()
{
    clock_t time1 = clock();
	#ifndef ONLINE_JUDGE
	//freopen("IN.in","r",stdin);
	#else
	//ONLINE_JUDGE
	#endif
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
    init();
    clock_t time2 = clock();
    cerr <<"Time: " <<(double)(time2-time1)/CLOCKS_PER_SEC * 100000 <<" seconds" <<endl;
	return 0;
}