Matthew McCauley directly appeals the within-Guidelines-range sentence the district court 1 imposed after he pled guilty to federal drug and identity-theft charges. His counsel has moved to withdraw, and has filed a brief under Anders v. California, 386 U.S. 738, 87 S.Ct. 1396, 18 L.Ed.2d 493 (1967), challenging the substantive reasonableness of McCauley’s sentence. In pro se supplemental briefs, McCauley additionally challenges the district court’s determination of the relevant drug quantity for Guidelines purposes.

Upon careful review, we conclude that McCauley’s sentence is not substantively unreasonable. See United States v. Feemster, 572 F.3d 455, 461 (8th Cir. 2009) (en banc) (abuse-of-discretion review). We furr ther conclude that McCauley’s drug-quantity challenge is foreclosed because he stipulated to the drug quantity in a sentencing agreement, which was adopted by the district court. See United States v. Olano, 507 U.S. 725, 733, 113 S.Ct. 1770, 123 L.Ed.2d 508 (1993); United States v. Nguyen, 46 F.3d 781, 783 (8th Cir. 1995). Finally, having independently reviewed the record pursuant to Penson v. Ohio, 488 U.S. 75, 109 S.Ct. 346, 102 L.Ed.2d 300 (1988), we find no nonfrivolous issues.

The judgment is affirmed, and we grant counsel’s motion to withdraw.