Fifty athletes stand in a row facing the coach, and count from left to right according to the coach's password. After reporting, the coach asks all athletes who reported multiples of 4 to take a step forward, and then asks all athletes who reported multiples of 6 to take a step forward. Multiple athletes take a step back. How many athletes are still in their original positions?
50名运动员面向教练站成一行，按教练的口令从左到右1-50顺序报数，报完后，教练员让所有报4的倍数的运动员向前迈一步，接着又让所有报6的倍数的运动员向后退一步．现在仍处在原来位置上的运动员有多少名．
<gadget id="calculator">50 - 12 - 8</gadget>
<output>30</output>

<gadget id="calculator">30 + 4</gadget>
<output>34</output>

<gadget id="calculator">34 + 4</gadget>
<output>38</output>

<result>38</result>