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()))
  A = [j for j in a]
  
  cnt1 = 0
  cnt2 = 0
  S = 0
  
  if a[0] > 0:
      for i in range(n - 1):
          S += a[i]
          if a[i] > 0:
              if S + a[i + 1] >= 0:
                  cnt1 += (
                      a[i + 1] + S + 1 if a[i + 1] + S + 1 > 0 else -(a[i + 1] + S + 1)
                  )
                  a[i + 1] = -1 - S
          elif a[i] < 0:
              if S + a[i + 1] <= 0:
                  cnt1 += (
                      a[i + 1] + S - 1 if a[i + 1] + S - 1 > 0 else -(a[i + 1] + S - 1)
                  )
                  a[i + 1] = 1 - S
      A[0] = -1
      cnt2 = a[0] + 1
      for i in range(n - 1):
          S += A[i]
          if A[i] > 0:
              if S + A[i + 1] >= 0:
                  cnt2 += (
                      A[i + 1] + S + 1 if A[i + 1] + S + 1 > 0 else -(A[i + 1] + S + 1)
                  )
                  A[i + 1] = -1 - S
          elif A[i] < 0:
              if S + A[i + 1] <= 0:
                  cnt2 += (
                      a[i + 1] + S - 1 if a[i + 1] + S - 1 > 0 else -(a[i + 1] + S - 1)
                  )
                  A[i + 1] = 1 - S
  elif a[0] < 0:
      for i in range(n - 1):
          S += a[i]
          if a[i] > 0:
              if S + a[i + 1] >= 0:
                  cnt1 += (
                      a[i + 1] + S + 1 if a[i + 1] + S + 1 > 0 else -(a[i + 1] + S + 1)
                  )
                  a[i + 1] = -1 - S
          elif a[i] < 0:
              if S + a[i + 1] <= 0:
                  cnt1 += (
                      a[i + 1] + S - 1 if a[i + 1] + S - 1 > 0 else -(a[i + 1] + S - 1)
                  )
                  a[i + 1] = 1 - S
      A[0] = 1
      cnt2 = -a[0] + 1
      for i in range(n - 1):
          S += A[i]
          if A[i] > 0:
              if S + A[i + 1] >= 0:
                  cnt2 += (
                      A[i + 1] + S + 1 if A[i + 1] + S + 1 > 0 else -(A[i + 1] + S + 1)
                  )
                  A[i + 1] = -1 - S
          elif A[i] < 0:
              if S + A[i + 1] <= 0:
                  cnt2 += (
                      a[i + 1] + S - 1 if a[i + 1] + S - 1 > 0 else -(a[i + 1] + S - 1)
                  )
                  A[i + 1] = 1 - S
  else:
      a[0] = 1
      cnt1 = 1
      for i in range(n - 1):
          S += a[i]
          if a[i] > 0:
              if S + a[i + 1] >= 0:
                  cnt1 += (
                      a[i + 1] + S + 1 if a[i + 1] + S + 1 > 0 else -(a[i + 1] + S + 1)
                  )
                  a[i + 1] = -1 - S
          elif a[i] < 0:
              if S + a[i + 1] <= 0:
                  cnt1 += (
                      a[i + 1] + S - 1 if a[i + 1] + S - 1 > 0 else -(a[i + 1] + S - 1)
                  )
                  a[i + 1] = 1 - S
      A[0] = -1
      cnt2 = 1
      for i in range(n - 1):
          S += A[i]
          if A[i] > 0:
              if S + A[i + 1] >= 0:
                  cnt2 += (
                      A[i + 1] + S + 1 if A[i + 1] + S + 1 > 0 else -(A[i + 1] + S + 1)
                  )
                  A[i + 1] = -1 - S
          elif A[i] < 0:
              if S + A[i + 1] <= 0:
                  cnt2 += (
                      a[i + 1] + S - 1 if a[i + 1] + S - 1 > 0 else -(a[i + 1] + S - 1)
                  )
                  A[i + 1] = 1 - S
  cnt = cnt2 if cnt1 >= cnt2 else cnt1
  
  print(cnt)
  
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"}]