Somewhere in ancient Europe, there was such a regulation: every time a merchant brought goods through a checkpoint, half of the coins would be confiscated, and one would be returned. There is a merchant who only has two coins left after passing 10 checkpoints. How many coins did the merchant have in total initially?
在古代欧洲某个地方有这样一个规定：商人带着商品每经过一个关口，就要被没收一半的钱币，再退还一个．有一个商人，在经过10个关口之后，只剩下两个钱币了，这个商人最初共有多少个钱币．
<gadget id="calculator">2 / 2</gadget>
<output>1</output>

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

<result>2</result>