new_contents: """
  Largest prime factor
  
  The prime factors of 13195 are 5, 7, 13 and 29.
  
  What is the largest prime factor of the number 600851475143 ?
  """
  
  import math 
  
  prime_to_check = 600851475143
  def is_prime(n):
      if n <= 3:
          return n >= 2
      if n % 2 == 0 or n % 3 == 0:
          return False
      for i in range(5, int(n ** 0.5) + 1, 6):
          if n % i == 0 or n % (i + 2) == 0:
              return False
      return True
  
  
  def find_largest_factor(prime_to_check):
  	i = math.trunc(math.sqrt(prime_to_check))
  	largest_factor = 0
  	while i > largest_factor:
  		if is_prime(i):
  			largest_factor = i
  		i = i - 1
  
  	return largest_factor
  		
  print find_largest_factor(prime_to_check)
  
subject: Create 3.py