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 sc = new Scanner(System.in);
	int N = sc.nextInt();
	int a[][] = new int[N][2];

	int checkV = sc.nextInt();
	int checkH = sc.nextInt();
	boolean fv = true;
	boolean fh = true;
	for (int i = 1; i < N; i++) {
	    a[i][0] = sc.nextInt();
	    a[i][1] = sc.nextInt();
	    if (checkV != a[i][0]) {
//		System.out.println(a[i][0]);
		fv = false;
	    }
	    if (checkH != a[i][1]) {
//		System.out.println(a[i][1]);
		fh = false;
	    }
	}
	if (fv == true || fh == true) {
	    System.out.println("YES");
	} else {
	    System.out.println("NO");
	}
    }
}