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();
        Integer xPos = null;
        Integer yPos = null;
        int xCount = 0;
        int yCount = 0;
        boolean ok = true;
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            if(xPos == null) {
                xPos = x;
            }
            if(xPos.intValue() == x) {
                xCount++;
            }
            int y = in.nextInt();
            if(yPos == null) {
                yPos = y;
            }
            if(yPos.intValue() == y) {
                yCount++;
            }
            
        }
        if(xCount == n || yCount == n) {
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    }
}