Task: Question Understanding
Input (English): We focus primarily on the smaller data set of 645 hand-labeled articles provided to task participants, both for training and for validation.  We pre-trained BERT-base on the 600,000 articles without labels by using the same Cloze task BIBREF5 that BERT had originally used for pre-training.  
 Question: How long is the dataset?
Output (English): Abstractive