A snail wants to climb a tree 10 meters high. It can climb 4.35 meters during the day, but every night when it falls asleep, it slides down 1.35 meters. How many days did it take for the snail to reach the top of the tree?
有一只蜗牛要爬到一棵高10米的树上．它白天能爬4.35米，但是每到晚上它睡着时，又滑下1.35米．这只蜗牛第几天才爬到树顶？
<result>3</result>