TAMPA, Fla. (WFLA) – An Indiana high school junior recently became the only student in the world to earn a perfect score on the AP calculus exam.

According to a press release on Penn High School’s website, Felix Zhang earned the honor after not missing a single question on the exam.

The College Board, which administers the exams, notified the school’s principal that Zhang not only earned a perfect score, but that he is the only student in the world to earn every point possible on the test.

“I felt pretty confident knowing that I knew what to do on the test, but there was always a chance I would make a small error or something. So I wasn’t really expecting to see a perfect score,” Zhang told local media. “And that was pretty surprising to me because I felt like, there’s a lot of other people out there who probably perform very well on this test, and I’m pretty surprised that no one else got a perfect score.”

The school said Zhang took the AP calculus exam last spring, when he was a sophomore, along with around 270,000 students worldwide.