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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
    int t;
    cin>>t;
    while(t-->0){
        int n;
        cin>>n;
        if(n<=3){
            cout<<"YES"<<endl;
        }
        else{
            cout<<"NO"<<endl;
        }
        vector<pair<int,int>> v;
        int xmin=INT_MAX,xmax=INT_MIN,xminymin=INT_MAX,xminymax=INT_MIN,xmaxymin=INT_MAX,xmaxymax=INT_MIN;
        while(n-->0){
            int x,y;
            cin>>x>>y;
            v.push_back(pair<int,int>(x,y));
            if(x<xmin){
                xmin=x;
                if(y<xminymin){
                    xminymin=y;
                }
                if(y>xminymax){
                    xminymax=y;
                }
            }
            if(x>xmax){
                xmax=x;
                if(y<xmaxymin){
                    xmaxymin=y;
                }
                if(y>xmaxymax){
                    xmaxymax=y;
                }
            }
            
        }
        
        
    }
    return 0;
}