A piece of iron wire, half of which is used for the first time is more than 2 meters, and the remaining half of which is used for the second time is less than 1 meter. At this time, there are still 5 meters left. Find the original length of the iron wire.
一根铁丝，第一次用去它的一半多2米，第二次用去剩下的一半少1米，这时还余5米，求铁丝原来的长度．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">8 + 2</gadget>
<output>10</output>

<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<result>20</result>