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) {
        try (Scanner in = new Scanner(System.in)) {
            int n = in.nextInt();
            int originalX = in.nextInt();
            int originalY = in.nextInt();
            boolean horizontal = true;
            boolean vertical = true;
            for (int a0 = 1; a0 < n; a0++) {
                int x = in.nextInt();
                int y = in.nextInt();
                if (x != originalX) {
                    horizontal = false;
                }
                if (y != originalY) {
                    vertical = false;
                }
            }
            if (horizontal || vertical) {
                System.out.println("YES");
            }
            else {
                System.out.println("NO");
            }
        }
    }
}