import string
file = ('A quick brown fox jumps over the lazy dog','A slow yellow fox crawls under the proactive dog')
for phrase in file:
result = ''
for x in list(string.lowercase[:26]):
if file[0].find(x) >= 0:
pass
else:
result = result + x
print result
aW1wb3J0IHN0cmluZwoKZmlsZSA9ICgnQSBxdWljayBicm93biBmb3gganVtcHMgb3ZlciB0aGUgbGF6eSBkb2cnLCdBIHNsb3cgeWVsbG93IGZveCBjcmF3bHMgdW5kZXIgdGhlIHByb2FjdGl2ZSBkb2cnKQpmb3IgcGhyYXNlIGluIGZpbGU6CglyZXN1bHQgPSAnJwoJZm9yIHggaW4gbGlzdChzdHJpbmcubG93ZXJjYXNlWzoyNl0pOgoJCWlmIGZpbGVbMF0uZmluZCh4KSA+PSAwOgoJCQlwYXNzCgkJZWxzZToKCQkJcmVzdWx0ID0gcmVzdWx0ICsgeAoJcHJpbnQgcmVzdWx0