code: 
  
  
  
  
  
  '''simple docstring'''
  
  
  
  
  def 	__lowerCamelCase (  UpperCAmelCase_       )      ->int:
  
  	# validate:
  	if not isinstance(UpperCAmelCase_				,							UpperCAmelCase_       ) or not all(
  	    isinstance(UpperCAmelCase_				,							UpperCAmelCase_       ) and item >= 0 for item in citations       ):
  		raise ValueError('The citations should be a list of non negative integers.'       )
  
  	citations.sort()
  	snake_case__  					=      len(UpperCAmelCase_       )
  
  	for i in range(UpperCAmelCase_       ):
  		if citations[len_citations - 1 - i] <= i:
  			return i
  
  	return len_citations
  
  
  if __name__ == "__main__":
  			import doctest
  
  			doctest.testmod()
  
  
  
  
style_context: 
  
  
  
  
  
  '''simple docstring'''
  
  
  
  
  def 	__lowerCamelCase (  UpperCAmelCase_       )      ->int:
  	return 1 if input_a == 0 else 0
  
  
  
  
  def 	__lowerCamelCase (  )      ->None:
  	assert not_gate(0       ) == 1
  	assert not_gate(1       ) == 0
  
  
  if __name__ == "__main__":
  			print(not_gate(0))
  			print(not_gate(1))
  
  
  
  