output_description: Print the minimum number of operations required, or `-1` if the objective
  cannot be achieved.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
      A_1 A_2 ... A_N
      B_1 B_2 ... B_N
attempt: import sys
  
  input = sys.stdin.readline
  sys.setrecursionlimit(100000)
  
  
  def getN():
      return int(input())
  
  
  def getList():
      return list(map(int, input().split()))
  
  
  import math
  
  n = getN()
  
  anums = getList()
  bnums = getList()
  ans = 0
  okay = [0 for i in range(n)]
  update = True
  while update:
      update = False
      for i in range(n):
          if not okay[i]:
              if i == n - 1:
                  j = 0
              else:
                  j = i + 1
              h = i - 1
              a, b, c, tgt = bnums[h], bnums[i], bnums[j], anums[i]
              # print(a,b,c)
              if b > max(a, c):
                  if tgt > b:
                      print(-1)
                      sys.exit()
                  if tgt != b:
                      dec = math.ceil((b - (max(a, c, tgt))) / (a + c))
                      bnums[i] -= dec * (a + c)
                      ans += dec
                      update = True
                      if anums[i] == bnums[i]:
                          okay[i] = 1
      # print(coll, anums, bnums)
  
  print(ans)
  
problem_description: Statement
  
  There are N positive integers arranged in a circle.
  
  Now, the i-th number is A_i. Takahashi wants the i-th number to be B_i. For
  this objective, he will repeatedly perform the following operation:
  
    * Choose an integer i such that 1 \leq i \leq N.
    * Let a, b, c be the (i-1)-th, i-th, and (i+1)-th numbers, respectively. Replace the i-th number with a+b+c.
  
  Here the 0-th number is the N-th number, and the (N+1)-th number is the 1-st
  number.
  
  Determine if Takahashi can achieve his objective. If the answer is yes, find
  the minimum number of operations required.
samples: [{"input": "3\n    1 1 1\n    13 5 7", "output": "4\n    \n\nTakahashi can achieve his objective by, for example, performing the following\noperations:\n\n  * Replace the second number with 3.\n  * Replace the second number with 5.\n  * Replace the third number with 7.\n  * Replace the first number with 13.\n\n* * *"}, {"input": "4\n    1 2 3 4\n    2 3 4 5", "output": "-1\n    \n\n* * *"}, {"input": "5\n    5 6 5 2 1\n    9817 1108 6890 4343 8704", "output": "25"}]