Except as provided in 42 Pa.C.S. § 9714 (relating to sentences for second and subsequent offenses), a person who has been convicted of a felony may be sentenced to imprisonment as follows:
(1) In the case of a felony of the first degree, for a term which shall be fixed by the court at not more than 20 years.
(2) In the case of a felony of the second degree, for a term which shall be fixed by the court at not more than ten years.
(3) In the case of a felony of the third degree, for a term which shall be fixed by the court at not more than seven years.