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 sameX = true, sameY = true;
        int prevX = in.nextInt(), prevY = in.nextInt();
        for(int a0 = 0; a0 < n - 1; a0++){
            int x = in.nextInt();
            int y = in.nextInt();
            if (x != prevX) sameX = false;
            if (y != prevY) sameY = false;
            prevX = x; prevY = y;
        }
        System.out.println(sameX || sameY ? "YES" : "NO");
    }
}