import java.awt.Point;
import java.io.*;
import java.io.ObjectInputStream.GetField;
import java.math.BigInteger;
import java.sql.Array;
import java.util.*;



class TestClass {

static long mod ;
static ArrayList<Integer>[] M;
static ArrayList<Integer>[] N;
static int[][] dp;
static int[] H;
static long[][][] E;
static long x;
static int n;


public static long rnd(){
    x = (x * 37 + 10007) % 1000000007;
    return x;
}

public static int  sign(){
    if(rnd() > 500000003)   return +1;
    return -1;
}

public static long rng(){
   long value = rnd();
    value *= sign();
    return value;
}

public static void init(){
    for(int i=0;i<n;i++)
        for(int j =i + 1;j<n;j++)
            for(int k =0;k<=n*n/4;k++)
                E[i][j][k] = rng();
}
public static void main(String args[] ) throws java.lang.Exception {



//InputStream inputStream = System.in;
//InputReader in = new InputReader(inputStream);

//BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
//BufferedReader in = new BufferedReader(new FileReader("C:\\Users\\Sompathak\\Desktop\\yes.txt"));
//Scanner in = new Scanner(new FileReader("C:\\Users\\Sompathak\\Desktop\\yes.java"));
//PrintWriter pw = new PrintWriter(new FileWriter("C:\\Users\\sompatha\\Desktop\\output.txt"));
//InputStream inputStream = System.in;
//InputReader in = new InputReader(inputStream);
Scanner in = new Scanner(new InputStreamReader(System.in));
//Scanner in = new Scanner(new FileReader("C:\\Users\\sompatha\\Desktop\\yes.txt"));
//we can we will ??? !!!!!! SOM RISES
//long startTime = System.currentTimeMillis();
//long startTime = System.currentTimeMillis();

//float endTime   = System.currentTimeMillis();
//float totalTime = (endTime - startTime)/(float)1000;
//System.out.println(totalTime+" sec....."); 

//in.hasNext()

mod = (long) (1e9+7);
int t = in.nextInt();
while(t>0){
	t--;
	int n = in.nextInt();
	ArrayList<Integer> X = new ArrayList<>();
	ArrayList<Integer> Y = new ArrayList<>();
	Point[] A = new Point[n];
	for(int i=0;i<n;i++){
		A[i] = new Point(in.nextInt(),in.nextInt());
		X.add(A[i].x);
		Y.add(A[i].y);
	}
	Collections.sort(X);
	Collections.sort(Y);
	
	int minx = X.get(0);
	int maxx = X.get(n-1);
	
	int miny = Y.get(0);
	int maxy = Y.get(n-1);
	boolean is_good=true;
	
	for(int i=0;i<n;i++)
		if(minx<A[i].x && maxx!=A[i].x && miny!=A[i].y && maxy!=A[i].y) is_good=false;
	int freqx=0;
	int f=0;
	for(int i=0;i<n;i++)
	  if(A[i].y==miny) f++;
	  else if(A[i].y==maxy) freqx++;
	
	//if(f<2 || freqx<2) is_good=false;
	
	System.out.println(is_good ? "YES":"NO");
	
	 
	
}


}public static class InputReader
{
private InputStream stream;
private byte[] buf = new byte[1024];
private int curChar;
private int numChars;
private SpaceCharFilter filter;

public InputReader(InputStream stream)
{
this.stream = stream;
}

public int read()
{
if (numChars == -1)
throw new InputMismatchException();
if (curChar >= numChars)
{
curChar = 0;
try
{
numChars = stream.read(buf);
} catch (IOException e)
{
throw new InputMismatchException();
}
if (numChars <= 0)
return -1;
}
return buf[curChar++];
}

public int nextInt()
{
int c = read();
while (isSpaceChar(c))
c = read();
int sgn = 1;
if (c == '-')
{
sgn = -1;
c = read();
}
int res = 0;
do
{
if (c < '0' || c > '9')
throw new InputMismatchException();
res *= 10;
res += c - '0';
c = read();
} while (!isSpaceChar(c));
return res * sgn;
}

public String readString()
{
int c = read();
while (isSpaceChar(c))
c = read();
StringBuilder res = new StringBuilder();
do
{
res.appendCodePoint(c);
c = read();
} while (!isSpaceChar(c));
return res.toString();
}
public double readDouble() {
int c = read();
while (isSpaceChar(c))
c = read();
int sgn = 1;
if (c == '-') {
sgn = -1;
c = read();
}
double res = 0;
while (!isSpaceChar(c) && c != '.') {
if (c == 'e' || c == 'E')
return res * Math.pow(10, nextInt());
if (c < '0' || c > '9')
throw new InputMismatchException();
res *= 10;
res += c - '0';
c = read();
}
if (c == '.') {
c = read();
double m = 1;
while (!isSpaceChar(c)) {
if (c == 'e' || c == 'E')
return res * Math.pow(10, nextInt());
if (c < '0' || c > '9')
throw new InputMismatchException();
m /= 10;
res += (c - '0') * m;
c = read();
}
}
return res * sgn;
}
public long readLong() {
int c = read();
while (isSpaceChar(c))
c = read();
int sgn = 1;
if (c == '-') {
sgn = -1;
c = read();
}
long res = 0;
do {
if (c < '0' || c > '9')
throw new InputMismatchException();
res *= 10;
res += c - '0';
c = read();
} while (!isSpaceChar(c));
return res * sgn;
}
public boolean isSpaceChar(int c)
{
if (filter != null)
return filter.isSpaceChar(c);
return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
}

public String next()
{
return readString();
}

public interface SpaceCharFilter
{
public boolean isSpaceChar(int ch);
}
}
}