>>> def f(lst):
... return sum(map(str.split, lst), [])
...
>>> words1 = ['AC Python', 'Mini GO', 'IronPython .NET', 'F# .Net Good']
>>> words2 = ['Python GO', 'Java AC', 'C# .Net Good', 'VB .Net', 'PHP Shit']
>>> words3 = set(f(words1)) & set(f(words2))
>>> words4 = filter(lambda i: len(i) == 2, words3)
>>> list(words4)
['AC', 'GO']
>>>
>>> def f(lst):
... return sum(map(str.split, lst), [])
...
>>> words1 = ['Abilify', 'Aciphex', 'Actos', 'Abelcet XO', 'Adderall XR', 'Advair Diskus', 'Ambien CR', 'Abelcet XX', 'Aricept', 'Atripla', 'Avandia', 'Avapro', 'Avastin', 'Avelox', 'Avodart', 'Avonex', 'Benicar', 'Boniva', 'Byetta', 'Caduet', 'Celebrex']
>>> words2 = ['Aammonium alum', 'abacavir', 'abatacept', 'Abbokinase', 'abciximab-injection', 'VV Abelcet', 'Abilify', 'Abreva', 'acamprosate calcium delayed-release tablet', 'Acanya', 'acarbose', 'Accolate', 'AccuNeb', 'Accupril', 'Accuretic', 'Accutane', 'Accutrim', 'ACE Inhibitors', 'acebutolol', 'Aceon', 'Acetadote', 'acetaminophen', 'acetaminophen ', 'acetaminophen-isometheptene-dichloralphenazone', 'Acetasol', 'Acetasol HC', 'acetazolamide-oral', 'acetic acid ', 'acetic acid-otic', 'acetic acid-oxyquinoline-ricinoleic acid-vaginal', 'acetohexamide', 'acetohydroxamic acid-oral', 'acetylcysteine-inhalation', 'acetylcysteine-injection', 'acetylsalicylic acid', 'Acid', 'Aciphex', 'acitretin-oral', 'Actemra', 'Actigall', 'Actimmune', 'Actinex', 'Actiq', 'Activase', 'Actonel', 'Actos', 'Acular', 'Acular LS', 'acyclovir', 'A-Hydrocort']
>>> words3 = set(f(words1)) & set(f(words2))
>>> words4 = filter(lambda i: len(i) == 2, words3)
>>> list(words4)
[]
>>> words3
{'Abilify', 'Abelcet', 'Actos', 'Aciphex'}
>>>