The cat runs up the stairs with 10 steps. How many different ways does it go up one step or two steps?
猫向有10个台阶的楼上跑去，它一步上1阶或2阶，共有多少种不同上法．
<gadget id="calculator">1 + 2</gadget>
<output>3</output>

<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<gadget id="calculator">3 + 5</gadget>
<output>8</output>

<gadget id="calculator">5 + 8</gadget>
<output>13</output>

<gadget id="calculator">8 + 13</gadget>
<output>21</output>

<gadget id="calculator">13 + 21</gadget>
<output>34</output>

<gadget id="calculator">21 + 34</gadget>
<output>55</output>

<gadget id="calculator">34 + 55</gadget>
<output>89</output>

<result>89</result>