42 CFR §456.651

For purposes of this subpart— Facility, with respect to inpatient psychiatric services for individuals under 21, includes a psychiatric program as specified in § 441.151 of this chapter. Level of care means one of the following types of inpatient services: hospital, mental hospital, intermediate care facility, or psychiatric services for individuals under 21. Long-stay services means services provided to a beneficiary after a total of 60 days of inpatient stay (90 in the case of mental hospital services) during a 12-month period beginning July 1, not counting days of stay paid for wholly or in part by Medicare.