The school has a rectangular playground. It is planned to use half of the long direction to build a basketball court. First, expand 7 meters to the east, and then expand 7 meters to the south and north, so that the area of the basketball court will increase by 798 square meters. Question: The original school playground What is the perimeter in meters?
学校有一长方形操场，计划沿着长的方向用一半建篮球场，先向东扩7米，再向南、北各扩7米，这样篮球场面积就增加了798平方米，问：原来学校操场的周长是多少米？
<gadget id="calculator">7 * 7 * 2</gadget>
<output>98</output>

<gadget id="calculator">798 - 98</gadget>
<output>700</output>

<gadget id="calculator">700 / 7</gadget>
<output>100</output>

<gadget id="calculator">100 * 2</gadget>
<output>200</output>

<result>200</result>