import java.io.*;
import java.util.*;

public class A {
	public static void main(String[] args) throws IOException {
        BufferedReader input = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer line = new StringTokenizer(input.readLine());

		int n = Integer.parseInt(line.nextToken());
		int[] xs = new int[n];
		int[] ys = new int[n];
		boolean vert = true, hori = true;

		for (int i = 0; i < n; i++) {
			line = new StringTokenizer(input.readLine());
			xs[i] = Integer.parseInt(line.nextToken());
			ys[i] = Integer.parseInt(line.nextToken());
		}

		for (int i = 1; i < n; i++) {
			if (xs[i] != xs[i - 1]) {
				vert = false;
			}
			if (ys[i] != ys[i - 1]) {
				hori = false;
			}
		}

		System.out.println((vert || hori) ? "YES" : "NO");
	}
}