import java.io.*; import java.util.*; import java.text.*; import java.math.*; import java.util.regex.*; public class Solution { public static void main(String[] args) { Scanner in = new Scanner(System.in); int n = in.nextInt(); int prev_x = -100000; int prev_y = -100000; boolean x_flag = true; boolean y_flag= true; int x_counter = 0 ; int y_counter = 0; for(int a0 = 0; a0 < n && ( x_flag || y_flag); a0++){ int x = in.nextInt(); int y = in.nextInt(); if (a0 == 0) { prev_x = x; prev_y = y; }else { if(x!=prev_x && y!=prev_y) { x_flag = false; y_flag = false; }else if(x!=prev_x ) x_flag = false; else if(y!= prev_y) y_flag = false; else { prev_x = x; prev_y = y; } } } if(x_flag || y_flag) System.out.println("YES"); else System.out.println("NO"); } }