Defendant appeals his sentence for assault in the third degree with a firearm. ORS 163.165. The trial court sentenced defendant to five years incarceration, with a two-year period of post-prison supervision (PPS). Defendant assigns error to that sentence, arguing that, under the sentencing guidelines, his total period of incarceration and PPS may not exceed the maximum indeterminate sentence for third degree assault, which is five years. ORS 161.605(3); OAR 213-05-002(4).

Defendant’s argument is unpreserved. Nevertheless, he urges us to review it as an error apparent on the face of the record. ORAP 5.45(2). We decline to do so. To be apparent on the face of the record, a trial court’s legal error must be “obvious” and “not reasonably in dispute.” State v. Brown, 310 Or 347, 355, 800 P2d 259 (1990). That requirement is not met here. The court was confronted with apparently inconsistent sentencing mandates; it was required to impose a sentence of five years, ORS 161.610(4)(a), required to impose PPS, OAR 213-05-002(1), and was directed that the total prison time and PPS not exceed the maximum indeterminate sentence for the crime of conviction, OAR 213-05-002(4), which is five years. ORS 161.605(3). Our cases do not explain how to balance those conflicting requirements. The issue is reasonably in dispute, and, accordingly, the trial court’s sentence is not error apparent on the face of the record. Brown, 310 Or at 355.

Affirmed.