The entire workflow of the reaction completion algorithm includes two sequential subunits, ChemBalancer and ChemMLM. The workflow is summarised in Figure . In the ChemBalancer subunit, the USPTO and Reaxys ® reactions were passed to ChemBalancer to determine if each reaction, exemplified by a reaction scheme "A+B+C → D+E", is originally complete, or could be balanced with ChemBalancer by adding a candidate reagent "R" or a help compound "H" into the reaction, or sometimes combinations of "R" and "H". The complete reactions, shown in the bottom red dashed box of Figure were used to train the ChemMLM model.