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();
        boolean linex = true;
        boolean liney = true;
        int x2 = 0, y2 = 0;
        for(int a0 = 0; a0 < n; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            if (a0 == 0) {
                x2 = x;
                y2 = y;
            } else {
                if (x2 != x)
                    linex = false;
                if (y2 != y)
                    liney = false;
                x2 = x;
                y2 = y;
            }
        }
        System.out.println(linex || liney ? "YES" : "NO");
    }
}