output_description: Print the answer as an integer.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
      A_0 A_1 A_2 \cdots A_N
attempt: from collections import deque
  
  n = int(input())
  A = list(map(int, input().split()))
  sum = 0
  maxNode = [2**i for i in range(n + 1)]
  que = deque()
  node = A[n]
  maxS = 0
  maxim = -1
  
  deep = n
  for i in range(node):
      que.appendleft(2 * node - i)
  maxS += A[n]
  while 0 < len(que) and 1 < deep:
      node = que.popleft()
      deep -= 1
      print(deep)
      allnode = A[deep] + node
      if 2 ** A[deep] > allnode:
          deep += 1
          continue
      maxS += allnode
      for i in range(A[deep]):
          que.appendleft(2 ** A[deep] - i)
      if deep == 1:
          maxim = max(maxS + A[0], maxim)
      maxS -= allnode
  print(maxim)
  
problem_description: Statement
  
  Given is an integer sequence of length N+1: A_0, A_1, A_2, \ldots, A_N. Is
  there a binary tree of depth N such that, for each d = 0, 1, \ldots, N, there
  are exactly A_d leaves at depth d? If such a tree exists, print the maximum
  possible number of vertices in such a tree; otherwise, print -1.
samples: [{"input": "3\n    0 1 1 2", "output": "7\n    \n\nBelow is the tree with the maximum possible number of vertices. It has seven\nvertices, so we should print 7.\n\n![0d8d99d13df036f23b0c9fcec52b842b.png](https://img.atcoder.jp/nomura2020/0d8d99d13df036f23b0c9fcec52b842b.png)\n\n* * *"}, {"input": "4\n    0 0 1 0 2", "output": "10\n    \n\n* * *"}, {"input": "2\n    0 3 1", "output": "-1\n    \n\n* * *"}, {"input": "1\n    1 1", "output": "-1\n    \n\n* * *"}, {"input": "10\n    0 0 1 1 2 3 5 8 13 21 34", "output": "264"}]