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())
  i = input()
  
  i = i.split()
  for item in range(len(i)):
      i[item] = int(i[item])
  
  totn = 0
  totp = 0
  
  countp = 0
  countn = 0
  
  for x in range(len(i)):
      totp += i[x]
      totn += i[x]
  '''    
      if x == 0:
          if totp == 0:   
              totn = -1
              countn = 1
  
              totp = 1
              countp = 1
              
          elif totp < 0:
              countp = abs(totp) + 1
              totp = 1
  
          elif totp > 0:
              countn = abs(totn) + 1
              totn = -1
  '''
      if x %2 == 1:
          if totn == 0:
              countn += 1
              totn = 1
          elif totn < 0:
              countn += abs(totn) + 1
              totn = 1
  
          if totp == 0:
              countp += 1
              totp = -1
          elif totp > 0:
              countp += abs(totp) + 1
              totp = -1
  
      elif x %2 == 0:
          if totn == 0:
              countn += 1
              totn = -1
          elif totn > 0:
              countn += abs(totn) + 1
              totn = -1
  
          if totp == 0:
              countp += 1
              totp = 1
          elif totp < 0:
              countp += abs(totp) + 1
              totp = 1
      '''print('totn', totn)
      print('countn', countn)
      print('totp', totp)
      print('countp', countp) '''   
  count = min(countn, countp)
  print(count)
  
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"}]