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 x = in.nextInt(); int y = in.nextInt(); boolean xFlag = true; boolean yFlag = true;
        for(int a0 = 1; a0 < n; a0++){
            int a = in.nextInt();
            int b = in.nextInt();
            if (x != a) xFlag = false;
            if (y != b) yFlag = false;
        }
        System.out.println((xFlag || yFlag) ? "YES" : "NO");
    }
}