After combining two identical squares into a rectangle, the perimeter and perimeter are reduced by 18 decimeters. What is the perimeter of the original square?
把两个一样的正方形，拼成一个长方形后，周长周长减少了18分米，问原来一个正方形的周长的周长是多少．
<gadget id="calculator">18 / 2</gadget>
<output>9</output>

<gadget id="calculator">9 * 4</gadget>
<output>36</output>

<result>36</result>