case class Point(x: Int, y: Int)  {
    def this(a: Array[Int]) = this(a(0), a(1))
}

object Solution {

    def main(args: Array[String]) {
       val q = io.StdIn.readInt;
        (1 to q).foreach{i =>
            val n = io.StdIn.readInt;
            val points = (1 to n).map(k => io.StdIn.readLine.split(" ").map(_.toInt))

            if (n == 1 || n == 2) {
                println("YES")
            }
            else {
                val p = points.map(x => Point(x(0), x(1)));
                val minX = p.map(i => i.x).min;
                val maxX = p.map(i => i.x).max;
                val minY = p.map(i => i.y).min;
                val maxY = p.map(i => i.y).max;
                
                val possible = p.forall(a => a.x == minX || a.x == maxX || a.y == minY ||  a.y == maxY)
                        
                if (possible) println("YES")
                else println("NO")
            }
        }
    }
}