Eight natural numbers are arranged in a row, starting from the third number, each number is equal to the sum of the two numbers before it. Given that the first number is 3 and the eighth number is 180, what is the second number. 3, □, □, □, □, □, □180.
八个自然数排成一行，从第三个数开始，每个数都等于它前面两个数的和．已知第一个数是3，第八个数是180，那么第二个数是多少.3，□，□，□，□，□，□180．
<gadget id="calculator">180 - 24</gadget>
<output>156</output>

<gadget id="calculator">156 / 13</gadget>
<output>12</output>

<result>12</result>