title: Choosing unique set representing number puzzle
body: <p>Following is the input set given.</p>
  
  <pre><code>1009 2000
  1009 2001
  1002 2002
  1003 2002 
  </code></pre>
  
  <p>Each line represents one group, Number represents ID of the member in the group. Problem is to choose minimum number of people which re-presents complete given set. Only one member should be choose from each Group. 2-tuple members will not repeated. But members can be part of more than one group.</p>
  
  <p>So in this example answer be <code>1009</code> and <code>2002</code> which represents the sets. <code>1009</code> is chosen because it is representing two team and same is the case for <code>2002</code>.</p>
  
  <p>I am looking for what algorithm can be used to solve this problem.</p>
  
  <p>Another example:</p>
  
  <pre><code>1009 2000
  1009 2001
  1002 2002
  1003 2002 
  1004 2003
  </code></pre>
  
  <p>Answer can be <code>{ 1009 , 2002, 1004}</code> or <code>{ 1009, 2002, 2003}</code></p>