def main():
result = 0
for num in range(2, 10001):
proper_sum = proper_divisor_sum(num)
if num != proper_sum and proper_divisor_sum(proper_sum) == num:
result += proper_sum
print(result)
def main():
limit, result = 20162, 0
abundant_numbers = set()
for num in range(1, limit):
if proper_divisor_sum(num) > num:
abundant_numbers.add(num)
if not any((num - x) in abundant_numbers for x in abundant_numbers):
result += num
print(result)