title: Boolean Algebra simplification (3 inputs)
body: <p>I may need your help with this quite simple thing:
  This -> <code>abc' + ab'c + a'bc + abc</code>
  can (I guess) be simplified to this -> <code>ab+ac+bc</code>.</p>
  
  <p>But how in the world is this done with <code>Boolean</code> algebra?</p>
  
  <p>I already reduced it to -> abc'+ab'c+bc by using the absorption rule on the last two terms <code>[a'bc + abc]</code>. But how can I reduce the rest of it to get the end result?</p>