please develop a entity relationship diagram

A health care organization keeps track of outpatient locations and examination rooms within the outpatient locations For each outpatient location it keeps track of the OLID (unique) and OLName For each examination rooms it keeps track of the ERoom Number (unique within its outpatient center, but examination rooms in different outpatient locations can have the same EroomNumber) and ERoomSize Each outpatient location must have at least one but can have many examination rooms and each examination room is located in one outpatient location