output_description: If it is possible to perform the operations so that the heights of the squares
  are non-decreasing from left to right, print `Yes`; otherwise, print `No`.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
      H_1 H_2 ... H_N
attempt: a, b, c = map(int, input().split())
  if (a - b) >= c:
      print(0)
  else:
      print(c - a + b)
  
problem_description: Statement
  
  There are N squares arranged in a row from left to right. The height of the
  i-th square from the left is H_i.
  
  For each square, you will perform either of the following operations once:
  
    * Decrease the height of the square by 1.
    * Do nothing.
  
  Determine if it is possible to perform the operations so that the heights of
  the squares are non-decreasing from left to right.
samples: [{"input": "5\n    1 2 1 1 3", "output": "Yes\n    \n\nYou can achieve the objective by decreasing the height of only the second\nsquare from the left by 1.\n\n* * *"}, {"input": "4\n    1 3 2 1", "output": "No\n    \n\n* * *"}, {"input": "5\n    1 2 3 4 5", "output": "Yes\n    \n\n* * *"}, {"input": "1\n    1000000000", "output": "Yes"}]