=begin

Let d(n) be defined as the sum of proper divisors of n (numbers less than n which divide evenly into n).
If d(a) = b and d(b) = a, where a ≠ b, then a and b are an amicable pair and each of a and b are called amicable numbers.

For example, the proper divisors of 220 are 1, 2, 4, 5, 10, 11, 20, 22, 44, 55 and 110; therefore d(220) = 284. The proper divisors of 284 are 1, 2, 4, 71 and 142; so d(284) = 220.

Evaluate the sum of all the amicable numbers under 10000.

=end

load 'library.rb'

max = 10000

@memoized = {}
def getFactorSum(num)
  if @memoized[num].nil?
    sum = 0
    findFactors(num).each {|f| sum += f }
    @memoized[num] = sum
  else
    sum = @memoized[num]
  end
  sum - num
end

total = 0
1.upto(max-1) do |n|
  sum = getFactorSum(n)
  if sum > n && sum < 10000 && n == getFactorSum(sum)
    total += n + sum
    print n.to_s+' '+sum.to_s+"\n"
  end
end

print total