def factorial(n):
  """
  This function calculates the factorial of a non-negative integer.
 
  Args:
    n: The non-negative integer for which to calculate the factorial.
 
  Returns:
    The factorial of n, or 1 if n is 0.
    Raises ValueError if n is negative.
  """
  if n < 0:
    raise ValueError("Factorial is not defined for negative numbers")
  elif n == 0:
    return 1
  else:
    result = 1
    for i in range(1, n + 1):
      result *= i
    return result
 
# Example usage:
number = 5
fact = factorial(number)
print(f"The factorial of {number} is {fact}") 

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