title: multiple set operations in python
body: <p>I am new to python and learning it now. I am practicing it online and came across with the below problem. I tried to solve it, however, though I am getting the expected result the online validator is saying it as wrong. Please suggest where I am going wrong.</p>
  
  <p>++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++</p>
  
  <blockquote>
    <p>In a school, there are total 20 students numbered from 1 to 20. You’re given three lists named ‘C’, ‘F’, and ‘H’, representing students who play cricket, football, and hockey, respectively. Based on this information, find out and print the following: </p>
    
    <ul>
    <li>Students who play all the three sports</li>
    <li>Students who play both cricket and football but don’t play hockey</li>
    <li>Students who play exactly two of the sports</li>
    <li>Students who don’t play any of the three sports</li>
    </ul>
    
    <p>Format:</p>
    
    <p>Input:</p>
    
    <blockquote>
      <p>3 lists containing numbers (ranging from 1 to 20) representing students who play cricket, football and hockey respectively.</p>
    </blockquote>
    
    <p>Output:</p>
    
    <blockquote>
      <p>4 different lists containing the students according to the constraints provided in the questions.</p>
    </blockquote>
  </blockquote>
  
  <p>Examples:
  Input:</p>
  
  <pre><code>[[2, 5, 9, 12, 13, 15, 16, 17, 18, 19]
  [2, 4, 5, 6, 7, 9, 13, 16]
  [1, 2, 5, 9, 10, 11, 12, 13, 15]] 
  </code></pre>
  
  <p>Expected Output:</p>
  
  <pre><code>[2, 5, 9, 13]
  [16]
  [12, 15, 16]
  [3, 8, 14, 20]
  </code></pre>
  
  <p>Below is my code </p>
  
  <pre><code>C = set(input_list[0])
  F = set(input_list[1])
  H = set(input_list[2])
  A= set(range(1, 21))
  
  print(sorted(list(C &amp; F &amp; H)))
  print(sorted(list((C &amp; F) - H)))
  print(sorted(list(((C-F)&amp;H | (C-H)&amp;F))))
  print(sorted(list(A-(C|F|H))))
  </code></pre>
  
  <p>I am not sure if A is really needed or not.</p>
  
  <p>Thanks,</p>