def algo(words):
    t = []
    for word in words:
       t.append((len(word), word))

    t.sort(key=lambda t: t[1][-1])

    res = []
    for l, w in t:
        res.append(w)

    res = filter(lambda t: 'a' in t, res) 

    return list(res)

if __name__=="__main__": 
    print(algo(["Pierre", "Jean", "Marie", "Eric", "Nathalie", "Yvonne"]))