As shares of GameStop continued to fall for the second day in a row on Tuesday, billionaire Mark Cuban offered words of wisdom to Reddit users who may have seen their fortunes take a turn for the worse after last week’s astounding rally.

“I learned some expensive lessons when I first started trading stocks,” the Shark Tank investor said during an AMA session when asked what advice he had for people who have lost money over the last few weeks. “It was painful. But I tried to learn what I got right and wrong. Right now, right here. The game is changing. The hard part is ask yourself if what you believed in has actually changed.”

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