In a mathematics competition, (1/7) students won the first prize, (1/3) students won the second prize, (1/2) students won the third prize, and the rest won the commemorative prize. It is known that there are less than 50 students participating in this competition, how many of them won the commemorative award?
一次数学竞赛，结果(1/7)的学生获得一等奖，(1/3)的学生获得二等奖，(1/2)的学生获得三等奖，其余获纪念奖．已知参加这次竞赛的学生不满50人，那么获得纪念奖的有多少人．
<gadget id="calculator">2 * 3 * 7</gadget>
<output>42</output>

<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (1/7) - (1/3) - (1/2)</gadget>
<output>1/42 = around 0.02381</output>

<gadget id="calculator">42 * (1/42)</gadget>
<output>1</output>

<result>1</result>