title: Operator overloading in Kotlin
body: <p>String division using operator overloading in <code>Kotlin</code>, please help me to complete this code. No change can be made in main function. 
  Find common from both string like <code>a=aabcc b=abdec answer=abc</code> (unique common characters)</p>
  
  <pre><code>fun main(args: Array&lt;String&gt;) 
  {
        val a:String = readLine()!!
  
        val b:String = readLine()!!
  
        val result = a/b
  
        println(result)
   }
  </code></pre>