A building has 4 floors underground and 18 floors above ground. Mr. Wang takes the elevator from 3 floors underground to 7 floors above ground. How many floors does the elevator go up in total?
某大楼地下共有4层，地上共有18层，王老师乘电梯从地下3层升到地上7层，电梯一共升了多少层．
<gadget id="calculator">7 - (-3) - 1</gadget>
<output>9</output>

<result>9</result>