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();
        int[] x = new int[n];
        int[] y = new int[n];
        for(int a0 = 0; a0 < n; a0++){
            x[a0] = in.nextInt();
            y[a0] = in.nextInt();
        }
        boolean matched_x = true, matched_y = true;
        for (int i = 0; i < n-1; i++) {
            if (x[i] != x[i+1]) matched_x = false;
            if (y[i] != y[i+1]) matched_y = false;
        }
        if ((!matched_x) && (!matched_y)) System.out.println("NO");
        else System.out.println("YES");
    }
}