Each of the 100 students has learned at least one of the three languages: English, French, and Russian. 41 students have studied English, 52 have studied French, 43 have studied Russian, and they have also studied English. There are 16 people who have learned French, 11 people who have studied English and Russian, and 15 people who have studied French and Russian. Question: How many people have learned all three languages?
100个学生每人至少学过英语、法语、俄语三门语言中的一个，学过英语的有41人，学过法语的有52人，学过俄语的有43人，学过英语也学过法语的有16人，学过英语也学过俄语的有11人，学过法语也学过俄语的有15人．问：三种语言都学过的有多少人？
<gadget id="calculator">41 + 52 + 43</gadget>
<output>136</output>

<gadget id="calculator">16 + 11 + 15</gadget>
<output>42</output>

<gadget id="calculator">136 - 42</gadget>
<output>94</output>

<gadget id="calculator">100 - 94</gadget>
<output>6</output>

<result>6</result>