To complement Table , the top-k invalidity is presented within Table . The reduction of invalid SMILES has been a central focus in template-free model research, with algorithms like TiedTransformer addressing this issue. However, what remains unexplored is the proportion of invalid molecules generated by semi-template models. From an algorithmic perspective, there is no guarantee that semi-template models would exclusively produce valid molecules, which is an essential aspect that has been overlooked. The table illustrates this oversight, showing that semi-template models generate a notable number of invalid molecules as k increases.