Taxi billing. The starting fare of a taxi is 5 yuan, and after 2 kilometers, it is charged at 1.2 yuan per kilometer (less than 1 kilometer is calculated as 1 kilometer). Uncle Wang spent 26.6 yuan in a taxi. How many kilometers did he travel at least?
出租车计费．出租车的起步价是5元，2千米以后按每千米1.2元计费(不足1千米按1千米计算)．王叔叔坐出租车用了26.6元车费，他至少行了多少千米？
<gadget id="calculator">26.6 - 5</gadget>
<output>21.6</output>

<gadget id="calculator">21.6 / 1.2</gadget>
<output>18</output>

<gadget id="calculator">18 + 2</gadget>
<output>20</output>

<result>20</result>