There are 49 students in the fourth grade who are arranged in a square formation at the opening ceremony of the school sports meeting. How many people are there in the outermost layer of the square formation?
四年级有49位同学在学校运动会开幕式上排列成方阵入场，这个方阵的最外层共有多少人．
<gadget id="calculator">7 * 4</gadget>
<output>28</output>

<gadget id="calculator">28 - 4</gadget>
<output>24</output>

<result>24</result>