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()))
  c = 0
  i = 1
  k = 1
  sum = a[0]
  
  while a[i] == 0:
  		i += 1
  	if a[i] > 0:
  		if i % 2 == 1:
  			a[0] = 1
  			c = 1
  		else:
  			a[0] = -1
  			c = 1
  	else:
  		if i % 2 == 1:
  			a[0] = -1
  			c = 1
  		else:
  			a[0] = 1
  			c = 1
  i = 1
  if a[0] > 0:
  	while i < n:
  		if i == 2*k-1:
  			sum = sum + a[2*k-1]
  			if sum >= 0:
  				c = c + sum + 1
  				sum = -1
  			else:
  				pass
  			i += 1
  		else:
  			sum = sum + a[2*k]
  			if sum <= 0:
  				c = c - sum + 1
  				sum = 1
  			else:
  				pass
  			i += 1
  			k += 1
  	print(c)
  elif a[0] < 0:
  	while i < n:
  		if i == 2*k-1:
  			sum = sum + a[2*k-1]
  			if sum <= 0:
  				c = c - sum + 1
  				sum = 1
  			else:
  				pass
  			i += 1
  		else:
  			sum = sum + a[2*k]
  			while sum >= 0:
  				c = c + sum + 1
  				sum = -1
  			else:
  				pass
  			i += 1
  			k += 1
  	print(c)
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"}]