Ding Ding and Lele each took a toy beetle to compete on the 400-meter track. Ding Ding's toy beetle ran 30 meters per minute, and Lele's toy beetle ran 20 meters per minute, but Lele brought a mysterious remote control. Pressing the first time will make Tintin's toy beetle go back at 10% of the original speed for 1 minute, and pressing the second time will make Tintin's toy beetle go back at 20% of the original speed for 1 minute. By analogy, press N times to make Tintin's toy beetle go backwards at the original speed N*10% for 1 minute. Then continue at the original speed. If Lele finally wins the game, how many times does he press the remote control at least. (type: variable speed)
丁丁和乐乐各拿了一辆玩具甲虫在400米跑道上进行比赛，丁丁的玩具甲虫每分钟跑30米，乐乐的玩具甲虫每分钟跑20米，但乐乐带了一个神秘遥控器，按第一次会使丁丁的玩具甲虫以原来速度的10%倒退1分钟，按第二次会使丁丁的玩具甲虫以原来速度的20%倒退1分钟．以此类推，按第N次，使丁丁的玩具甲虫以原来的速度N*10%倒退1分钟．然后再按原来的速度继续前进．如果乐乐在比赛中最后获胜，他最少按多少次遥控器．(类型：变速)
<result>6</result>