The tortoise and the hare race, the whole journey is 2000m, the first round the tortoise climbs 20m per minute, and the rabbit runs 400m per minute. The rabbit thought it was fast, and fell asleep on the way, but when the tortoise reached the finish line, the rabbit was still 800m away from the finish line. In the second round, how long can the rabbit sleep at most to ensure that the game is not lost?
龟兔赛跑，全程2000m，第一轮龟每分钟爬20m，兔每分钟跑400m．兔自以为速度快，在途中睡了一觉，结果龟到达终点时，兔距离终点还有800m．第二轮，兔子要保证比赛不输，最多可睡多久？
<gadget id="calculator">2_000 / 20</gadget>
<output>100</output>

<gadget id="calculator">2_000 / 400</gadget>
<output>5</output>

<gadget id="calculator">100 - 5</gadget>
<output>95</output>

<result>95</result>