President Donald Trump can shrug off being labeled a “tyrant” or even a “dictator,” but there’s one insult he says he simply can’t stand.The 79-year-old president revealed at a rally on Friday that being called “dumb” bothered him so much that he decided to take a cognitive test to silence critics questioning his mental sharpness.“They hit me with a bad one: He’s a dumb person. D-U-M, not the B,” Trump told the crowd, The Daily Beast reports. “Most people don’t know it has a B.”Trump was speaking to supporters at at Rockland Community College in New York at what was billed as a rally focused on affordability. But the the president launched into a story about a conversation he had with his doctor after critics questioned his mental acuity earlier this month. “I said, ‘Doctor, I don’t mind being called a brilliant tyrant dictator, but I don’t want to be called dumb,’” the president said.Trump revealed the insult he hates the most while speaking to supporters at a rally at Rockland Community College in Suffern, New York on Friday (Reuters)“‘What do I do, doctor? Is there some kind of test I can take?’ He said, ‘Actually, sir, there is. It’s a cognitive test.’ I said, ‘How many presidents have taken it?’ ‘None… No people have taken it.’ I said, ‘Well, is it good or bad? Is it tough?’”Trump went on to describe the test in detail, telling supporters the questions “start off easy” before becoming increasingly difficult.“So, the first question was: you have a bear, a snake, an elephant, and a horse. Name the horse. That’s the horse,” Trump said, acting out the exchange.“But toward the end, they had a question, like, ‘Pick a number sir, any number. OK, 203. Multiply times nine, divide by two, add on 1324 subtract 1292. Sir. Multiply it out one more time by 19. What’s the answer, sir?’“And I got it right,” Trump claimed.Trump’s comments come just days before he is expected to undergo another cognitive evaluation at Walter Reed Hospital on Monday for a medical and dental checkup – his fourth publicized examination since returning to office, the The Daily Beast reports.The president has previously boasted about passing cognitive exams, specifically the Montreal Cognitive Assessment, or MoCA, a screening tool commonly used to detect cognitive impairment and dementia. Meanwhile, Trump has frequently mocks former President Joe Biden over age-related concerns while insisting he remains in strong health.