Elements in File1: 1. Hi 2. March 3. Aug 4. Sept 5. Oct Elements in File2: 1. March 2. Hi 3. Bye 4. Aug 5. Dec Elements in File3: 1. Hi 2. March 3. Aug 4. Sept 5. Oct Elements in File4: 1. Hi 2. March 3. Aug 4. Bye 5. Dec