#include<iostream>
using namespace std;
int main()
{
	int q;
	cin>>q;

	while(q--)
	{
		
		int n;
		cin>>n;
		int a[n],b[n];
		int x,y;
		if(n==2 || n==3)
		{
			for(int i=1;i<=n;i++)
			{
				cin>>x>>y;
			}
			cout<<"YES"<<"\n";
		}
		else
		{
			
		for(int i=1;i<=n;i++)
		{
			a[i]=0;
			b[i]=0;
		}
			
		for(int i=1;i<=n;i++)
		{
			cin>>x;
			cin>>y;
			a[i]=x;
			b[i]=y;
		}
			
			int flag=0;
		for(int i=1;i<=n;i++)
		{
			for(int j=i+1;j<=n;j++)
			{
				if(a[i]!=a[j] || b[i]!=b[j] )
				{
					flag=1;
				}
				
				
			}
		
		}
		if(flag==0)
		{
			cout<<"YES"<<"\n";
		}
		else
		cout<<"NO"<<"\n";
		
	}
}
	
}