object Solution {

    def main(args: Array[String]) {
        val sc = new java.util.Scanner (System.in);
        var n = sc.nextInt();
        var l = List[(Int, Int)]()
        var a0 = 0;
        while(a0 < n){
            var x = sc.nextInt();
            var y = sc.nextInt();
            l = l :+ (x, y)
            a0+=1;
        }
        if (l.map (_._1).distinct.length == 1 || l.map(_._2).distinct.length == 1) println ("YES")
        else println ("NO")
    }
}