In recent years, there has been a surge of interest in performing end-to-end relation extraction, jointly recognizing entities and relations given free text inputs (Li and Ji, 2014; Miwa and Sasaki, 2014; <cite>Miwa and Bansal, 2016</cite>; . End-to-end learning prevents error propagation in the pipeline approach, and allows cross-task dependencies to be modeled explicitly for entity recognition.