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 curX = in.nextInt();
        int curY = in.nextInt();
        boolean yesX = true;
        boolean yesY = true;
        
        for(int a0 = 1; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            if (yesX) {
                yesX = x == curX;
            }
            if (yesY) {
                yesY = y == curY;
            }
            if (!yesX && !yesY) {
                System.out.println("NO");
                return;
            }
        }
        if (yesX || yesY) {
            System.out.println("YES");
            return;
        } else {
            System.out.println("NO");
                return;
        }
    }
}