awk - Split a text file based on delimiter using linux command line -

I have a file with the following lines of text:

  Jeremy, Thomas, 123 Peter, Paul, 456 Jack, Jill, 789   
 I would like to delete all the data except the center item, for example, ending with a file containing:  < Pre>  Thomas Paul jill   
 I have tried so many strange patterns that my brain is exploding. Any help would be appreciated.   
 
 
 Try  awk :  
  Awk -F '[[: space:]] *, [[space:]]' '{print $ 2}' input.txt