output_description: Print the score.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N Z W
      a_1 a_2 ... a_N
attempt: n,z,w=map(int,input().split())
  a[] = map(int,input().split())
  print(max(abs(a[-1]-w,a[-1]-a[-2]))
problem_description: Statement
  
  We have a deck consisting of N cards. Each card has an integer written on it.
  The integer on the i-th card from the top is a_i.
  
  Two people X and Y will play a game using this deck. Initially, X has a card
  with Z written on it in his hand, and Y has a card with W written on it in his
  hand. Then, starting from X, they will alternately perform the following
  action:
  
    * Draw some number of cards from the top of the deck. Then, discard the card in his hand and keep the last drawn card instead. Here, at least one card must be drawn.
  
  The game ends when there is no more card in the deck. The score of the game is
  the absolute difference of the integers written on the cards in the two
  players' hand.
  
  X will play the game so that the score will be maximized, and Y will play the
  game so that the score will be minimized. What will be the score of the game?
samples: [{"input": "3 100 100\n    10 1000 100", "output": "900\n    \n\nIf X draws two cards first, Y will draw the last card, and the score will be\n|1000 - 100| = 900.\n\n* * *"}, {"input": "3 100 1000\n    10 100 100", "output": "900\n    \n\nIf X draws all the cards first, the score will be |1000 - 100| = 900.\n\n* * *"}, {"input": "5 1 1\n    1 1 1 1 1", "output": "0\n    \n\n* * *"}, {"input": "1 1 1\n    1000000000", "output": "999999999"}]