Princess Terrana has been practicing all year to reach the summit of one of the mountain ranges in Shenkuu. Since the princess knows she isn't ready, she has been testing her skills on a small hill that is 240 metres high. Although Princess Terrana has gotten quite good at using her grappling hook, she is still rather clumsy. Every minute, she can shoot up 10 metres but slips back 5 metres. On average, how many minutes does it take Princess Terrana to reach the top of the hill?
Please enter an integer as the answer.
