new_contents: import math
  
  def primeFactors(n):
      listSize = int(math.sqrt(n)) + 1
      nonPrimes = [0] * listSize
      i = 2
  
      while (i * i < n):
          # if i is a known non-prime, nothing to do
          if nonPrimes[i] == 1:
             pass
  
          # otherwise, i is a prime
          else:
              if (n % i == 0):
                  # i is a prime factor, so mark all its multiples as ineligible (not prime)
                  j = i
                  while (j * j < n):
                      nonPrimes[j] = 1
                      j += i
  
                  print i
          i += 1
  
  primeFactors(600851475143)
  
subject: add prime factors code for Problem 3