Sangha means a community of adherents; Since you mentioned "three" facts, my guess therefore is the TRIpitaka. The Tripitaka writings of early schools of Buddhism, which were originally memorized and recited orally by disciples, fall into three general categories and are traditionally classified in three baskets (tri-pitaka). The commonest order is the following. The first category, the Vinaya Pitaka, was the code of ethics to be obeyed by the early sangha, monks and nuns. According to the scriptural account, these were invented on a day-to-day basis as the Buddha encountered various behavior problems with the monks. The second category, the Sutra Pitaka (literally "basket of threads", Pali: Sutta Pitaka), consists primarily of accounts of the Buddha's teachings. The Sutra Pitaka has numerous subdivisions: it contains more than 10,000 sutras. The third category is the Abhidharma Pitaka. This is applied to very different collections in different versions of the Tripitaka. In the Pali Canon of the Theravada there is an Abhidhamma Pitaka consisting of seven books. An Abhidharma Pitaka of the Sarvastivada school survives, also in seven books, six in Chinese and one in Tibetan. These are different books from the Pali ones though there are some common material and ideas. Another work surviving in Chinese, the Sariputrabhidharmasastra, may be all or part of another Abhidharma Pitaka. At least some other early schools of Buddhism had Abhidharma Pitakas, which are now lost.