object Solution {

    def main(args: Array[String]) {
        val sc = new java.util.Scanner (System.in);
        var n = sc.nextInt();
        var a0 = 0;
        var possibleHorizontalLine = true
        var possibleVerticalLine = true
        var lastX : Option[Int] = None
        var lastY : Option[Int] = None
 
        while(a0 < n){
            var x = sc.nextInt();
            var y = sc.nextInt();
            a0+=1;
            
            if (lastX.isEmpty) {
                lastX = Some(x)
                lastY = Some(y)
            } else {
                if (possibleHorizontalLine && ! lastX.contains(x))
                    possibleHorizontalLine = false;
                if (possibleVerticalLine && ! lastY.contains(y))
                    possibleVerticalLine = false;                  
            }
            
            
            
        }
        println(if (possibleHorizontalLine || possibleVerticalLine) "YES" else "NO")
    }
}