region:us
Top 20 hits for queries from training data in "MS-MARCO v2 passage" by Lucene Searcher (using pyserini)  
hits@20 0.1957  
See also : https://github.com/castorini/pyserini/blob/master/docs/prebuilt-indexes.md  
For java11 installation in linux : https://stackoverflow.com/questions/52504825/how-to-install-jdk-11-under-ubuntu  
