#include<iostream>
    #include<algorithm>
    #include<vector>
    #include<set>
    #include<limits.h>
    #include<map>
    #include<stack>
    #include<stdio.h>
    #include<queue>
    #include<math.h>
    #include<string.h>
    #include<sstream>

    using namespace std;
    #define fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    #define LL long long int
    #define pb push_back
    #define mp make_pair
    #define ff first
    #define ss second
    #define PII pair<int,int>
    #define PLL pair<LL,LL>
    #define VSP vector<set<PLL > > 
    #define PIS pair< int,string>

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
    fast
    int t,n,i,j,x,f=0;
        cin>>t;
    vector<int> v1,v2;
    while(t--)
        {
           cin>>n;
        int a[n][2];
         v1.clear();
        v2.clear();
          for(x=0;x<n;x++)
              {
                 cin>>i>>j;
                 a[x][0]=i;
                 a[x][1]=j;
                 v1.pb(i);
                  v2.pb(j);
               }
        sort(v1.begin(),v1.end());
        sort(v2.begin(),v2.end());
       // cout<<v1[0]<<" "<<v1[n-1]<<" "<<v2[0]<<" "<<v2[n-1];
          for(x=0;x<n;x++)
              {
                if((a[x][0]==v1[n-1] ) || (a[x][0]==v1[0] ) || (a[x][1]==v2[n-1] ) || (a[x][1]==v2[0] ))
                    {
                        if(a[x][0]==v1[n-1] && (a[x][1]>v2[n-1] && a[x][1]<v2[0]))
                            {
                               f=1;
                            //cout<<"gd\n";
                                break;
                            }
                           if(a[x][0]==v1[0] && (a[x][1]>v2[n-1] && a[x][1]<v2[0]))
                            {
                               f=1;
                               //cout<<"yfg\n";
                                break;
                            }
                              if(a[x][1]==v2[n-1] && (a[x][0]>v1[n-1] && a[x][0]<v1[0]))
                            {
                               f=1;
                                 // cout<<"ddsf\n";
                                break;
                            }
                                  if(a[x][1]==v2[0] && (a[x][0]>v1[n-1] && a[x][0]<v1[0]))
                            {
                               f=1;
                                     // cout<"dfsds\n";
                                break;
                            }
                }
                else
                {
                    f=1;
                    break;
                }
          }
        if(f==1)
            cout<<"NO\n";
        else
            cout<<"YES\n";
        f=0;
          
          
    }
    return 0;
}