Xiao Ming's family lives on the 4th floor. It takes him 1 minute to go up each floor. How many minutes does it take Xiao Ming to walk from the first floor to the fourth floor?
小明家住在4楼，他每上一层楼需要1分钟，小明从一层走到四层要几分钟？
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">3 * 1</gadget>
<output>3</output>

<result>3</result>