Among the 100 students, only one student has never studied a foreign language, 39 students have studied English, 49 students have studied French, 41 students have studied Russian, 14 students have studied English and French, and 14 students have studied English. There are 13 people who have studied Russian, and 9 people who have studied French and Russian. Question: How many people have learned all three languages?
100个学生只有一人没学过外语，学过英语的有39人，学过法语的有49人，学过俄语的有41人，学过英语也学过法语的有14人，学过英语也学过俄语的有13人，学过法语也学过俄语的有9人．问：三种语言都学过的有多少人？
<gadget id="calculator">41 - 14 - 13 - 9</gadget>
<output>5</output>

<gadget id="calculator">39 + 49 + 5</gadget>
<output>93</output>

<gadget id="calculator">99 - 93</gadget>
<output>6</output>

<result>6</result>