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();
        HashSet<Integer> xset = new HashSet<Integer>();
        HashSet<Integer> yset = new HashSet<Integer>();
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            xset.add(x);
            yset.add(y);
        }
        if((xset.size() == n && yset.size() == 1) || (xset.size() == 1 && yset.size() == n)){
            System.out.println("YES");
        } else {
            System.out.println("NO");
        }
    }
}