Stars Jonah Hill, Channing Tatum, and Ice Cube; Directed by Phil Lord and Chris Miller from a script by Michael Bacall and Jonah Hill, inspired by the television series; Rated R; 109 minutes; Critic’s grade: B-

Let’s start with the bottom line: For a fairly unambitious, middle of the road, mismatched-buddies/cop flick, “21 Jump Street” is surprisingly entertaining, mostly owing to the funny, perfectly timed line readings and slapstick action of lead actors Jonah Hill and Channing Tatum. The two give immensely winning performances, and they make for a Mutt & Jeff act I’d happily watch again.

Like so many recent remakes, “21 Jump Street” has little to do with its source material, the late ’80s television series of the same name. In fact, it’s surprising that anyone in Hollywoodland thought there was any residual cache from the title: Will members of the target audience even realize that the TV show featured a young Johnny Depp?

The relationship is the thing here, and it’s all about a bromance that decidedly was not brotherly love at first sight. Back in their high school days, Jenko (Tatum) was handsome but rather dimwitted, and he belonged to the jocks-and-cheerleaders set. True to Screenwriting 101 rules, Schmidt (Hill) was the opposite, a chubby, braces-wearing kid who had some smarts but was transformed into a clumsy oaf when it came to dealing with girls. The two could hardly be pals.

Flash forward a number of years to the police academy. There, Schmidt handily eases his way through the academic work, but is physically unfit. Jenko is still lean and strong, but he’s a lost cause when it comes to exams. It’s movie love at second sight, and the two become quick allies, helping each other get over their respective hurdles and make it to graduation day. As shorts-wearing bicycle cops, they share in the embarrassment of a bust gone hilariously wrong.

The focus of the story, of course (as in the series) takes place at the local high school, where the new pals are assigned to go undercover as students, in order to break up a drug ring headed by a Big Man on Campus played by Dave Franco (younger brother of James; the two share a similarly appealing puppyish but eccentric quality).

In a snafu, Schmidt gets the easy-A classes while Jenko winds up taking AP Chemistry and the like. Thus, they get to relive high school, and enjoy (or not) social roles completely opposite to the ones they played the first time around. Yes, romantic entanglements and complications ensue — Jenko isn’t as dumb as he looks (or pretends to look), and Schmidt doesn’t always have the right answers.

Thanks to a smart, frequently very funny screenplay, co-written by Hill, and brisk — but not too speedy — editing, directors Phil Lord and Chris Miller (“Cloudy With a Chance of Meatballs”) drive the movie along to its satisfying, if predictable conclusion.

All that, inspired turns by Ice Cube and Nick Offerman (“Parks and Recreation”) and a script with more penis jokes than any movie in film history. What more could one ask for from a contemporary comedy?