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 fx = in.nextInt();
        int fy = in.nextInt();
        boolean isSameLine = true;
        boolean isSameColumn = true;
        for(int a0 = 1; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            if (fx != x) {
                isSameLine = false;
            }
            if (fy != y) {
                isSameColumn = false;
            }
            if (!isSameLine && !isSameColumn) {
                break;
            }
        }
        if (!isSameLine && !isSameColumn) {
            System.out.println("NO");
        }
        else{
            System.out.println("YES");
        }
    }
}