Does 18 U.S.C. § 2113(a) define a single offense or two separate and divisible offenses?

QUESTION PRESENTED In Prince v. United States, 352 U.S. 322 (1957), this Court construed the first and second paragraphs of 18 U.S.C. § 2113(a)—bank robbery and entry into a bank with intent to commit a crime—as a single offense punishable by twenty years in prison. The Fifth Circuit nonetheless held that the two paragraphs define separate and divisible crimes. Does 18 U.S.C. § 2113(a) define a single offense or two separate and divisible offenses? i