There are 100 people lined up in a row, counting from 1 to 3 from left to right, those who reported to 3 stay, the rest leave the line, second time among the remaining students to count from 1 to 3, and those who reported to 3 stay , the rest leave the team, and go down in turn. The last person to leave is the number of people from left to right at the beginning.
有100个人排成一排，从左往右1至3报数，凡报到3的留下，其余离开队伍，第二次在留下的学生中再1至3报数，凡报到3的留下，其余离开队伍，依次下去，最后离开的人在开始时是从左往右的第多少个人．
<gadget id="calculator">3 ** 4</gadget>
<output>81</output>

<result>81</result>