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();
        Map<Integer, Integer> hMap = new HashMap<>();
        Map<Integer, Integer> vMap = new HashMap<>();
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            vMap.put(x, y);
            hMap.put(y, x);
        }
        if(vMap.size() != 1 && hMap.size() != 1) {
            System.out.println("NO");
        } else {
            System.out.println("YES");
        }
    }
    
}