What is the relevant jurisdiction for a motion of appeal against a judgment of conviction for sexual assault against a defendant who filed his notice of appeal pro se?

Ahearn pleaded guilty on September 14, 2015, and a judgment of conviction was entered on July 20, 2016. He filed his notice of appeal pro se on April 17, 2017. Although Ahearn's notice of appeal is untimely, the government waives any objection to untimeliness. Under the circumstances, we exercise our discretion to hear the appeal as though it were timely filed. See United States v. Frias, 521 F.3d 229, 232 (2d Cir. 2008) (holding that Federal Rule of Appellate Procedure 4(b) is not jurisdictional).