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: # https://atcoder.jp/contests/abc059/tasks/arc072_a
  # C - Sequence
  import copy
  
  N = int(input().split()[0])
  a_list = list(map(int, input().split()))
  
  w_list_1 = copy.copy(a_list)
  w_list_2 = copy.copy(a_list)
  c_1, c_2 = 0, 0
  s_1, s_2 = 0, 0
  c_list = []
  
  for i in range(N):  # 10 ** 5
      # 偶数項を正にする場合
      before = w_list_1[i]
      s_1 += before
  
      if i % 2 == 0 and s_1 < 0:
          w_list_1[i] += abs(s_1)
          c_1 += abs(s_1)
      elif i % 2 != 0 and s_1 >= 0:
          w_list_1[i] -= abs(s_1 + 1)
          c_1 += abs(s_1 + 1)
  
      s_1 = s_1 - before + w_list_1[i]
  
      if s_1 == 0:
          a = w_list_1[i]
          w_list_1[i] = a + 1 if a >= 0 else a - 1
          s_1 = 1 if a >= 0 else -1
          c_1 += 1
  
      # 偶数項を負にする場合
      before = w_list_2[i]
      s_2 += before
  
      if i % 2 == 1 and s_2 < 0:
          w_list_2[i] += abs(s_2)
          c_2 += abs(s_2)
      elif i % 2 != 1 and s_2 >= 0:
          w_list_2[i] -= abs(s_2 + 1)
          c_2 += abs(s_2 + 1)
  
      s_2 = s_2 - before + w_list_2[i]
  
      if s_2 == 0:
          a = w_list_2[i]
          w_list_2[i] = a + 1 if a >= 0 else a - 1
          s_2 = 1 if a >= 0 else -1
          c_2 += 1
  
  ans = min([c_1, c_2])
  print(ans)
  
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"}]