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())
  A = list(map(int, input().split()))
  counter = 0            ####操作回数
  A.reverse()
  S = 0           
  a = A.pop()
  if a==0:
    counter += 1
    while A:
      b = A.pop()
      if b == 0:
        counter += 2
      elif b>0:
        A.append(b)
        S = -1
        break
      elif b<0:
        A.append(b)
        S = 1
        break
  else:
    S += a
      
      
  while A:
    c = A.pop()
    if c>=0 and S>0:
      counter += abs(c+S)+1
      S = -1
    elif c<=0 and S<0:
      counter += abs(c+S)+1
      S = 1
    elif (c>=0 and S<0) and S+c<=0:
      counter += abs(S+c)+1
      S = 1
    elif (c=<0 and S>0) and S+c>=0:
      counter += abs(S+c)+1
      S = -1    
    else:
      S += c
      
  print(counter)
  
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"}]