#include<bits/stdc++.h>
using namespace std ;
#define pb push_back
#define mp make_pair
#define infile() freopen("large.in","r",stdin);
#define output() freopen("output.txt","w",stdout);
#define ll long long
#define sc(t); scanf("%d",&t);
#define scl(t); scanf("%lld",&t);
#define sc2(n,m); scanf("%d%d",&n,&m);
#define scl2(n,m); scanf("%lld%lld",&n,&m);
#define nl; printf("\n");
#define debug(); printf("tushar\n");

set < ll > :: iterator it ;
vector < ll > v ;
int n ;
int main()
{
int i , j , t  , q ;
sc(q) ; 
while(q--)
{
	sc(n) ; 
	int x[101] , y[101] ;
	set < int > s1,s2 ;
	for(i=1;i<=n;i++)
	{
		scanf("%d %d",&x[i],&y[i]) ; 
		s1.insert(x[i]) ; 
		s2.insert(y[i]) ; 
		
	}
	if(s1.size()<=2 && s2.size() <= 2)
	printf("YES\n") ; 
	else
	printf("NO\n") ; 
}
return 0 ;
}