title: removing duplicates from a list and combining it in Lisp
body: <p>I have a following type of list </p>
  
  <pre><code>(("abc" "12" "45")
   ("abc" "34" "56")
   ("cdb" "56" "78")
   ("deg" "90" "67")
   ("deg" "45" "34"))
  </code></pre>
  
  <p>and desired output is </p>
  
  <pre><code>(("abc" "12" "45" "34" "56")
   ("cdb" "56" "78")
   ("deg" "90" "67" "45 "34)).
  </code></pre>
  
  <p>What is the right approach for the same in Lisp?</p>