In the example shown in Fig. , the monomer polymerizes to Nylon 10 by means of a polycondensation process. The algorithm's Assigner routine identifies two functional groups in the monomer: an amino group and a carboxylic acid group. By accessing the dictionary that maps the functional groups to polymer classes, the algorithm verifies that both groups indicate the polyamide class and the polycondensation mechanism. The head assignment is performed by finding the atom mapping for the nitrogen of the amino group and the tail assignment is performed by finding the atom mapping for the carbon of the carboxylic acid group.