Yang Ping's family lives in Room 6, Floor 7, Unit 2, Building 4, Jiayuan Community, number 4-2-706. Li Li's family lives in Room 3, Floor 5, Unit 3, Building 7, Jiayuan District. What is Li Li's family number?
杨萍家住在佳园小区4号楼2单元7层6号房间，编号是4-2-706．李丽家住在佳园小区7号楼3单元5层3号房间，李丽家的编号是多少．
<gadget id="calculator">7 - 3 - 503</gadget>
<output>-499</output>

<result>-499</result>