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();
        boolean xS = true, yS  = true;
        int initialX = sc.nextInt();
        int initialY = sc.nextInt();
        for(int i=0;i<n-1;i++){
            int x = sc.nextInt();
            int y = sc.nextInt();
            xS = (x == initialX)?(true && xS):(false && xS);
            yS = (y == initialY)?(true && yS):(false && yS);
        }
        System.out.println((xS || yS)?"YES":"NO");
    }
}