Chess, having originated 15 centuries ago, continues to live and develop, using all modern technical means. However, despite this, no one, not excluding the world champion, has yet learned to play flawlessly. Alas, the mental capabilities of man are not unlimited. Chess engines can check for errors in your game in a matter of seconds and suggest how you should play.
We have not yet learned how to write a computer engine, but we will try to write a program that checks the answers.
There is such a task: “A four-digit number is given as input to the program. If it is symmetric, print 1, otherwise print any other integer”.
As you already know, all tasks are checked on pre-prepared examples and the correct answers to them.
It seems to a novice programmer that he has solved this problem, but for some reason the system does not accept his solution. A novice programmer thinks that this is due to the fact that he displays not the any other number that is written in the correct answers.
Help the programmer. Write a program that, based on the answer recorded in the testing system and the programmer's answer, determines whether the problem is solved correctly.
Input
The program receives two numbers as input: the answer recorded in the testing system and the student's answer.
Imprint
The program should output
YES if the student gave the correct answer and
NO otherwise.
Examples
| # |
Input |
Output |
| 1 |
11
-1 |
YES |
| 2 |
3
1 |
NO |