Ordered that the sentence is modified, on the law, by reducing the term of imprisonment from an indeterminate term of 10 to 20 years imprisonment to an indeterminate term of 6 2/3 to 20 years imprisonment; as so modified, the sentence is affirmed.
The defendant was sentenced as part of a plea agreement to an indeterminate term of 10 to 20 years imprisonment for manslaughter in the first degree based on the mistaken belief of the court and the parties that the crime was an armed felony offense. Since manslaughter in the first degree is not an armed felony offense, the minimum term of imprisonment should have been one-third, rather than one-half, of the maximum term ( see, CPL 1.20; Penal Law § 125.20, 70.02 Penal [3],[4]). The defendant does not seek to withdraw his plea. Accordingly, we have reduced the sentence to an indeterminate term of 6 2/3 to 20 years imprisonment ( see, People v. Spears, 228 A.D.2d 193; People v. Ayala, 194 A.D.2d 617).
Mangano, P.J., Bracken, O'Brien, Pizzuto and Florio, JJ., concur.