(AP) - In a pep talk that kept clear of politics,President Barack Obama on Tuesday challenged the nation's studentsto take pride and ownership in their education - and stick with iteven if they don't like every class or must overcome toughcircumstances at home.

"Every single one of you has something that you're good at.Every single one of you has something to offer," Obama toldstudents at Wakefield High School in Washington and childrenwatching his speech on television in schools across the country."And you have a responsibility to yourself to discover what thatis."

Presidents often visit schools, and Obama was not the first oneto offer a back-to-school address aimed at millions of students inevery grade. Yet this speech came with a dose of controversy, asseveral conservative organizations and many concerned parentswarned Obama was trying to sell his political agenda. That concernwas caused in part by an accompanying administration lesson planencouraging students to "help the president," which the WhiteHouse later revised.

Obama preceded his broad-scale talk with a meeting withWakefield students, where at one point he advised them to "becareful what you post on Facebook. Whatever you do, it will bepulled up later in your life."

Obama, accompanied by Education Secretary Arne Duncan, met withsome 40 students gathered in a school library before the speechcarried on ESPN and on the White House Web site.

The uproar over his speech followed him across the PotomacRiver, as his motorcade was greeted by a small band of protesters.One carried a sign exclaiming: "Mr. President, stay away from ourkids."

Duncan acknowledged Tuesday that some of the prepared guidancefor school officials included a suggestion that students couldcompose essays stating how they could help support Obama - an ideathe education secretary acknowledged was wrongheaded.

Obama proceeded later with the speech the White House hadreleased a day early, virtually unchanged. The school he chose asthe setting for his talk - Wakefield - is the most economically andracially diverse school in Arlington County, according to theDepartment of Education. Nearly 40 percent of graduating seniorspass an Advanced Placement test. That's more than twice thenational average.

"There is no excuse for not trying" he said in the speech. Hesaid students must be individually responsible for their education,and that it's important to work hard, pay attention in school andcomplete assignments.

"Whatever you resolve to do, I want you to commit to it,"Obama said. "The truth is, being successful is hard. You won'tlove every subject that you study. You won't click with everyteacher that you have."