
    Design a fraud detection algorithm that identifies potential coordinated fraud by finding pairs of suspicious transactions where the sum of all proper divisors of the first transaction amount equals the second transaction amount, and vice versa, up to a specified transaction limit. The system should calculate the total sum of all such paired transaction amounts to assess the scope of potential coordinated fraud activity.
    

    
def amicable_numbers_sum(limit):
    """
    Design a fraud detection algorithm that identifies potential coordinated fraud by finding pairs of suspicious transactions where the sum of all proper divisors of the first transaction amount equals the second transaction amount, and vice versa, up to a specified transaction limit. The system should calculate the total sum of all such paired transaction amounts to assess the scope of potential coordinated fraud activity.
    

    """
def amicable_numbers_sum(limit):
    """
    Design a fraud detection algorithm that identifies potential coordinated fraud by finding pairs of suspicious transactions where the sum of all proper divisors of the first transaction amount equals the second transaction amount, and vice versa, up to a specified transaction limit. The system should calculate the total sum of all such paired transaction amounts to assess the scope of potential coordinated fraud activity.
    

    """
    if not isinstance(limit, int):
        return 'Input is not an integer!'
    if limit < 1:
        return 'Input must be bigger than 0!'
    amicables = set()
    for num in range(2, limit + 1):
        if num in amicables:
            continue
        sum_fact = sum([fact for fact in range(1, num) if num % fact == 0])
        sum_fact2 = sum([fact for fact in range(1, sum_fact) if sum_fact % fact == 0])
        if num == sum_fact2 and num != sum_fact:
            amicables.add(num)
            amicables.add(sum_fact2)
    return sum(amicables)