def NOAJS_metric(bpmn_graph):
activities_count = all_activities_count(bpmn_graph)<EOL>gateways_count = all_gateways_count(bpmn_graph)<EOL>return activities_count + gateways_count<EOL>
Returns the value of the NOAJS metric (Number of Activities, joins and splits)
for the BPMNDiagramGraph instance.

:param bpmn_graph: an instance of BpmnDiagramGraph representing BPMN model.