16 students line up in a row, with an interval of 2 meters between every two students. How many meters is the distance from the first student to the last student?
16个学生排成一行，每两个人之间间隔2米．第一个学生到最后一个学生相距多少米．
<gadget id="calculator">16 - 1</gadget>
<output>15</output>

<gadget id="calculator">15 * 2</gadget>
<output>30</output>

<result>30</result>