There is a 5-meter-high bamboo pole, and a naughty little snail climbs to the top of the bamboo pole. It climbs down 3 meters during the day and climbs up 2 meters at night. How many days does it take for the little snail to climb to the ground?
有一根5米高的竹竿，一只调皮的小蜗牛，爬到竹竿的最顶端．它白天往下爬3米，到了晚上又向上爬2米．小蜗牛第多少天才能爬到地面．
<gadget id="calculator">5 - 3</gadget>
<output>2</output>

<gadget id="calculator">3 - 2</gadget>
<output>1</output>

<gadget id="calculator">2 / 1</gadget>
<output>2</output>

<gadget id="calculator">2 + 1</gadget>
<output>3</output>

<result>3</result>