//Author: AKSHAY VASANDANI FROM JAYPEE INSTITUTE OF INFORMATION TECHNOLOGY
 
 
 
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
#define ll long long
#define gcd __gcd
#include<bits/stdc++.h>
#define fi first
#define se second
#define mod 1000000007
#define pb push_back
#define N 100001
#define eb emplace_back
//#include <boost/multiprecision/cpp_int.hpp>
//#define bigint boost::multiprecision::cpp_int
 
using namespace std;
//using namespace __gnu_pbds;
/*typedef tree<
int,
null_type,
less<int>,
rb_tree_tag,
tree_order_statistics_node_update>
ordered_set;
 
 
ordered_set gset[100001];
*/
 
 
int readInt () {
	bool minus = false;
	int result = 0;
	char ch;
	ch = getchar();
	while (true) {
		if (ch == '-') break;
		if (ch >= '0' && ch <= '9') break;
		ch = getchar();
	}
	if (ch == '-') minus = true; else result = ch-'0';
	while (true) {
		ch = getchar();
		if (ch < '0' || ch > '9') break;
		result = result*10 + (ch - '0');
	}
	if (minus)
		return -result;
	else
		return result;
}
 
ll readLong () {
	bool minus = false;
	ll result = 0;
	char ch;
	ch = getchar();
	while (true) {
		if (ch == '-') break;
		if (ch >= '0' && ch <= '9') break;
		ch = getchar();
	}
	if (ch == '-') minus = true; else result = ch-'0';
	while (true) {
		ch = getchar();
		if (ch < '0' || ch > '9') break;
		result = result*10 + (ch - '0');
	}
	if (minus)
		return -result;
	else
		return result;
}
 
 
ll p(ll a,ll b)
{
    ll temp;
    if(b==0)
    return 1;
    temp=p(a,b/2)%mod;
    if(b&1)
    return (((a*temp)%mod)*temp)%mod;
    else
    return (temp*temp)%mod;
}
 
 
 int i,j,n,m,q,u,h,t,k,a,b,c,d;
 
 int s,de,f,e,g,cnt,l,x,y,r,mi,h1;

pair<int,int> ar[200001];

ll minn(ll a,ll b)
{
	if(a<=b)
	return a;
	return b;

}
int main()
{
q=readInt();
    while(q--)
        {
        set<int>sex;
        set<int>sey;
        set<pair<int,int>>se;
    n=readInt();
         for(i=1;i<=n;i++)
            {
ar[i].fi=readInt();
             sex.insert(ar[i].fi);
             ar[i].se=readInt();
             sey.insert(ar[i].se);
             se.insert({ar[i].fi,ar[i].se});
         }
        if(n==1 ||se.size()==1)
            {
             cout<<"YES"<<endl;
           continue;
        }
       int cnt=0;
      
        pair<int,int> ar3[30];
        h=0;
        for(auto it=se.begin();it!=se.end();it++)
            {
            pair<int,int>pa=*it;
            ar3[h].fi=pa.fi;
            ar3[h].se=pa.se;
            h++;
        }
        if(h==1)
            {
            cout<<"YES"<<endl;
            continue;
        }
         int cn1=0;
       i=0;
        int ex2=ar3[h-1].fi;
       int ex1=ar3[0].fi;
       int ak3=ar3[0].se;
            while(i<h && ar3[i].fi==ex1 )
                {
               cn1++;
                  i++;
            }
      int ak1=ar3[i-1].se;
       
          int i1=i;
        i=h-1;
         int ak2=ar3[h-1].se;
         while(i>=i1 && ar3[i].fi==ex2 )
                {
              cn1++;
                  i--;
            }
       
        int ak4=ar3[i+1].se;
     
        int i2=i;
        /*int h1=0;
        pair<int,int> ar4[234];
        for(i=i1;i<=i2;i++)
            {
           ar4[h1].fi=ar3[i].se;
            ar4[h1].se=ar3[i].fi;
            h1++;
        }
        sort(ar4,ar4+h1);
         
         i=0;
      int ey2=ar4[h1-1].fi;
       int ey1=ar4[0].fi;
       
            while(i<h1 && ar4[i].fi==ey1 )
                {
               cn1++;
                  i++;
            }
           i1=i;
        i=i1;
        while(i<h1 && ar4[i].fi==ey2 )
                {
               cn1++;
                  i++;
            }
       cout<<ak1<<" "<<ak2<<" "<<ak3<<" "<<ak4<<" "<<ey2<<" "<<ey1<<endl;
       */
        sey.clear();
        for(i=i1;i<=i2;i++)
            {
            sey.insert(ar3[i].se);
        }
        if(sey.size()>2)
            {
            cout<<"NO"<<endl;
        }
        else
            {
            if(sey.size()==2)
                {
                auto it=sey.end();
                it--;
                if(*it>=max(ak1,ak2))
                    {
                    it--;
                    if(*it<=min(ak3,ak4))
                        {
                        cout<<"YES"<<endl;
                    }
                    else
                        cout<<"NO"<<endl;
                }
            }
            else if(sey.size()==0)
                {
                cout<<"YES"<<endl;
            }
            else
                {
                 auto it=sey.end();
                it--;
                if(*it>=max(ak1,ak2) || *it<=min(ak3,ak4))
                    cout<<"YES"<<endl;
                else
                    cout<<"NO"<<endl;
            }
        }
       
    }
	return 0;
}