Nonetheless remarkable progress have been achieved with the use of seq2seq models (Gehrmann et al., 2018; See et al., 2017; Chopra et al., 2016; Rush et al., 2015) and a reward instead of loss function via deep-reinforcement learning<cite> (Chen and Bansal, 2018</cite>; Paulus et al., 2017; Ranzato et al., 2015) .