Defendant was convicted of conspiracy to commit murder, ORS 163.115; ORS 161.450, and was sentenced to 90 months’ imprisonment and 20 years’ post-prison supervision, less time served in prison. On appeal, defendant argues that the 20-year term exceeds the maximum allowable term of post-prison supervision. She acknowledges that she did not raise that issue before the trial court but argues that we should review the matter as plain error. The state concedes that the imposition of a 20-year term was plain error. We agree and accept that concession. Because defendant has a significant liberty interest at stake, and because the state has no valid interest in requiring defendant to serve an unlawful sentence, we exercise our discretion to correct the error.

Sentence vacated; remanded for resentencing; otherwise affirmed.