Finding Dataset size from Experiment ID

I need to find Dataset size from Experiment ID for reporting purposes. I’ve looked at Mongodb/meteor and can’t figure out where this information is stored. Python code below gives me experiment and result:
client = MongoClient(host, 38001)
db = client[‘meteor’]
cur = db.experiments.find({“uid”:experimentID})
experiment =
results = db.results.find({“exp_id”:experiment["_id"]})
count = results.count()
result = results[count-1]

I can get to db.datasets.find({"_id":experiment[‘dataset_id’]}) but can’t find how to calculate the size of the dataset.

Thanks for any input,

I was able to find this info from events collection. Here is a code sample to get particle count:
for item in{‘job_id’:dataset[‘vis_job_id’]}):
if ‘Loaded Dataset with’ in item[‘text’]:
particle_count = item[‘text’].split()[3]