Unable to understand question clearly

hi,
I am unable to understand the ques clearly.
As per what I have understood, the submission says wrong answer.
And what is the l and r in contraint l <= r <= 1000 ??
And according to question, we have to assign a and b values such that their xor value is the maximum value, but since there are only two value, we can either set different values for a and b or we can choose same values, right. But we also know that same bits will always give 0, then the xor of different a and b will be the answer, but that is giving wrong answer. I also gave conditional to find out which one will be maximum among them, but that also gives wrong answer.
Please clear what does the question exactly says and what are l and r in contraints l <= r <= 1000.

@shailendrakr.sk constraints are given for x and y
You are given two numbers x and y, now you can pick many pairs (a,b) from the range [x, y] and each of these pairs will have a xor value. You have to pick the pair whose xor value is the maximum.

I hope I’ve cleared your doubt. I ask you to please rate your experience here
Your feedback is very important. It helps us improve our platform and hence provide you
the learning experience you deserve.

On the off chance, you still have some questions or not find the answers satisfactory, you may reopen
the doubt.