I solved the problem and got wrong answers. I thought about every aspect of this problem and read the statement many times. But the result was just Wrong Answers. So I decided to change my mind and think about the mistakes could be in the problem statement. I found the mistake which is "In the inputs, n is not even, even the statement said it is!" I think the writers of the problems should be more careful about the statement and the inputs and outputs.

The n in the input is even. The problem might be somewhere else.