def sum_difference(first_lists, second_lists):
    first_sum = 0
    second_sum = 0

    for first_list in first_lists:
        first_sum += first_list

    for second_list in second_lists:
        second_sum += second_list

    return first_sum - second_sum

print(sum_difference([12,4,6,3,4], [6,8,3,3]))