Give this a shot
exceptions = set("belize cambodge mexique mozambique zaire zimbabwe".split())
vowels = set('aeiou')
plurals = set("etats-unis pays-bas".split())
word, sentinel = "", "quit"
while word != sentinel:
word = input("Enter the name of a country: ")
if word == sentinel:
continue
male = word in exceptions or word[-1].lower() not in vowels
plurality = word in plurals
apo = word[0].lower() in vowels
if apo:
print("l'%s" %word)
elif plurality:
print("les", word)
else:
print("le" if male else "la", word)