Hi, KAIDONG2008 team!
I guess you can see the task in this way:
Then, you are free to not use Y_i, or to use a different approach, i.e., not based on a classical Ml classifier.
We will soon publish on the website some details about the evaluation process, so these aspects (how to face the future situation involving more data sets) will become clearer.
For the time being, using one data set, please just name it X2.csv.
NOTICE that the toy data set (i.e., X1) is no longer evaluated--you just have X2 now.