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 tests = in.nextInt();
		int[] x = new int[tests];
		int[] y = new int[tests];

		for (int i = 0; i < tests; i++) {
			x[i] = in.nextInt();
			y[i] = in.nextInt();
		}


		if (sameElements(x) == true || sameElements(y) == true) {
			System.out.println("YES");
		} else {
			System.out.println("NO");
		}

	}

	public static boolean sameElements(int[] array) {
		if (array.length == 0) {
			return true;
		} else {
			int first = array[0];
			for (int element : array) {
				if (element != first) {
					return false;
				}
			}
			return true;
		}
	}
}