Fiona's-Problem

Some nerds in Barcelona decided to do a sober night at their airbnb, after going out the day before. Inspiration for their evening activity was delivered by Fiona, who gave them a math problem as dessert for dinner. All were keen to solve it, but soon realized that the problem stated by the wise catalan, is harder to solve than they thought. Suddenly, someone said : "Let's just code it with brute-force". The time flew by and at 3.09h in the morning they called it a day. They came closer to the solution, but did not finish the problem due to implementation issues.