To celebrate Children's Day, the children lined up in a square line. Regardless of counting from the front, from the back, or from the left or right, Li Li was the fifth. How many children are there in the line?
为庆祝六一，小朋友们排成正方形的队伍，无论从前、从后数，还是从左、从右数，李丽都在第5个，队伍一共有多少个小朋友？
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">5 + 4</gadget>
<output>9</output>

<gadget id="calculator">9 * 9</gadget>
<output>81</output>

<result>81</result>