output_description: Print the minimum necessary count of operations.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      n
      a_1 a_2 ... a_n
attempt: n = int(input())
  lis = list(map(int,input().split()))
  cou = 0
  co = 0
  ans1 = 0
  ans2 = 0
  for i in range(n):
    cou += lis[i]
    co += lis[i]
    if cou <= 0 and i % 2 == 0:
      ans1 += (1 -cou)
      cou = 1
    if cou => 0 and i % 2 == 1:
      ans1 += (cou +1)
      cou = -1
    if co => 0 and i % 2 == 0:
      ans2 += (co +1)
      co = -1
    if co <= 0 and i % 2 == 1:
      ans2 += (1 -co)
      co = 1
  print(min(ans1,ans2))
problem_description: Statement
  
  You are given an integer sequence of length N. The i-th term in the sequence
  is a_i. In one operation, you can select a term and either increment or
  decrement it by one.
  
  At least how many operations are necessary to satisfy the following
  conditions?
  
    * For every i (1≤i≤n), the sum of the terms from the 1-st through i-th term is not zero.
    * For every i (1≤i≤n-1), the sign of the sum of the terms from the 1-st through i-th term, is different from the sign of the sum of the terms from the 1-st through (i+1)-th term.
samples: [{"input": "4\n    1 -3 1 0", "output": "4\n    \n\nFor example, the given sequence can be transformed into 1, -2, 2, -2 by four\noperations. The sums of the first one, two, three and four terms are 1, -1, 1\nand -1, respectively, which satisfy the conditions.\n\n* * *"}, {"input": "5\n    3 -6 4 -5 7", "output": "0\n    \n\nThe given sequence already satisfies the conditions.\n\n* * *"}, {"input": "6\n    -1 4 3 2 -5 4", "output": "8"}]