output_description: Print the minimum number of operations required to achieve the objective.
  
  * * *
input_description: The input is given from Standard Input in the following format:
  
      
      
      N x
      a_1 a_2 ... a_N
attempt: n, x = map(int, input().split())
  ar = list(map(int, input().split()))
  pr, ans = 0, 0
  for e in ar:
      if pr + e > x:
          l = pr + e - x
          ans += l
          e -= l
      pr = e
  print(ans)
  
problem_description: Statement
  
  There are N boxes arranged in a row. Initially, the i-th box from the left
  contains a_i candies.
  
  Snuke can perform the following operation any number of times:
  
    * Choose a box containing at least one candy, and eat one of the candies in the chosen box.
  
  His objective is as follows:
  
    * Any two neighboring boxes contain at most x candies in total.
  
  Find the minimum number of operations required to achieve the objective.
samples: [{"input": "3 3\n    2 2 2", "output": "1\n    \n\nEat one candy in the second box. Then, the number of candies in each box\nbecomes (2, 1, 2).\n\n* * *"}, {"input": "6 1\n    1 6 1 2 0 4", "output": "11\n    \n\nFor example, eat six candies in the second box, two in the fourth box, and\nthree in the sixth box. Then, the number of candies in each box becomes (1, 0,\n1, 0, 0, 1).\n\n* * *"}, {"input": "5 9\n    3 1 4 1 5", "output": "0\n    \n\nThe objective is already achieved without performing operations.\n\n* * *"}, {"input": "2 0\n    5 5", "output": "10\n    \n\nAll the candies need to be eaten."}]