ब्रिटिश अधिकारी जॉन स्मिथ द्वारा अजंता की गुफाओं की खोज किस वर्ष की गई थी?

In Ancient Indian Statecraft, Kautilya's 'Rajamandala' theory primarily deals with:

The First Buddhist Council was held at ______.

Which ancient Indian text contains references indicating that population counts or census-like records were maintained in ancient India?