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


int main() {
    int q;
    cin>>q;
    for ( int tt=0;tt<q;tt++){
        int n;
        cin>>n;
        vector< pair< int, int > > s,v,v2;
        for ( int i = 0 ; i <n ; i++ ){
            int x, y;
            cin>>x>>y;
          	s.push_back( make_pair( x, y ) );
          	v.push_back(make_pair( x , y ) );  
         	v2.push_back( make_pair( y , x ) );
         	
        }
        sort( v.begin(), v.end() );
        sort( v2.begin() , v2.end() );
        bool K = 0;
        for ( int i = 0 ; i <n ; i++ ){
        	bool ok = 0;
        	if ( (s[ i ].first == v[ 0 ].first) || ( s[ i ].first == v[ n - 1 ].first ) ) ok = 1;
        	if ( (s[ i ].second == v2[ 0 ].first) || ( s[ i ].second == v2[ n - 1 ].first ) ) ok = 1;
        	if ( ok == 0 ){
        		K = 1;
        	}	
        }
        if ( K ){
        	puts("NO");
        }else puts("YES");
        
    }
    return 0;
}