Given two-dimensional points in space, determine whether they lie on some vertical or horizontal line. If yes, print YES; otherwise, print NO.
Input Format
The first line contains a single positive integer, , denoting the number of points.
Each line of subsequent lines contain two space-separated integers detailing the respective values of and (i.e., the coordinates of the point).
Constraints
Output Format
Print YES if all points lie on some horizontal or vertical line; otherwise, print NO.
Sample Input 0
5
0 1
0 2
0 3
0 4
0 5
Sample Output 0
YES
Explanation 0
All points lie on a vertical line.
Sample Input 1
5
0 1
0 2
1 3
0 4
0 5
Sample Output 1
NO
Explanation 1
The points do not all form a horizontal or vertical line.