output_description: Find the flavor of the apple pie made of the remaining N-1 apples when you
  optimally choose the apple to eat.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N L
attempt: n = [int(i) for i in input().split()]
  array = []
  abs_array = []
  for i in range(n[0]):
      array.append(n[1] + i - 1)
      abs_array.append(abs(n[1] + i - 1))
  abs_array = abs_array.sort()
  if abs_array[0] in array == True:
      print(sum(array) - abs_array[0])
  else:
      print(sum(array) + abs_array[0])
  
problem_description: Statement
  
  You have N apples, called Apple 1, Apple 2, Apple 3, ..., Apple N. The
  _flavor_ of Apple i is L+i-1, which can be negative.
  
  You can make an apple pie using one or more of the apples. The flavor of the
  apple pie will be the sum of the flavors of the apples used.
  
  You planned to make an apple pie using all of the apples, but being hungry
  tempts you to eat one of them, which can no longer be used to make the apple
  pie.
  
  You want to make an apple pie that is as similar as possible to the one that
  you planned to make. Thus, you will choose the apple to eat so that the flavor
  of the apple pie made of the remaining N-1 apples will have the smallest
  possible absolute difference from the flavor of the apple pie made of all the
  N apples.
  
  Find the flavor of the apple pie made of the remaining N-1 apples when you
  choose the apple to eat as above.
  
  We can prove that this value is uniquely determined.
samples: [{"input": "5 2", "output": "18\n    \n\nThe flavors of Apple 1, 2, 3, 4, and 5 are 2, 3, 4, 5, and 6, respectively.\nThe optimal choice is to eat Apple 1, so the answer is 3+4+5+6=18.\n\n* * *"}, {"input": "3 -1", "output": "0\n    \n\nThe flavors of Apple 1, 2, and 3 are -1, 0, and 1, respectively. The optimal\nchoice is to eat Apple 2, so the answer is (-1)+1=0.\n\n* * *"}, {"input": "30 -50", "output": "-1044"}]