There are 12 keys and 12 locks (a certain key can just open a certain lock), but I don't know which key matches which lock, and how many times I try to open at most, the lock and the key can be paired.
现有12把钥匙和12把锁(某一把钥匙恰好可以打开某一把锁)，但不知哪把钥匙配哪把锁，最多试开多少次，就能把锁和钥匙配对．
<gadget id="calculator">11 + 1</gadget>
<output>12</output>

<gadget id="calculator">11 / 2</gadget>
<output>11/2 = around 5.5</output>

<gadget id="calculator">12 * (11/2)</gadget>
<output>66</output>

<result>66</result>