list_1 = [[5, 3, 4], [1, 5, 8], [6, 4, 2]]
list_2 = [[8, 3, 4], [1, 5, 9], [6, 7, 2]]
final = []
for i in range(0, len(list_1)):
[final.append(x) for x in reversed([y for y in set(list_1[i]) ^ set(list_2[i])])]
print final
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