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 xValue = in.nextInt();
        int yValue = in.nextInt();
        boolean compareX = true;
        boolean compareY = true;
        for(int a0 = 0; a0 < n - 1; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            if (xValue != x) {
                compareX = false;
            }
            if (yValue != y) {
                compareY = false;
            }
        }
        if (compareX || compareY) {
            System.out.println("YES");
        }
        else {System.out.println("NO");}
    }
}