output_description: Print the minimum number of bricks that need to be broken to satisfy Snuke's
  desire, or print `-1` if his desire is unsatisfiable.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
      a_1 a_2 ... a_N
attempt: x = int(input())
  li = list(map(int, input()))
  from collections import deque
  
  l = deque(li)
  
  
  def m(p, lis):
      for i in range(len(lis)):
          if lis.leftpop() == p:
              return i + 1
      return -1
  
  
  print(m(x, l))
  
problem_description: Statement
  
  We have N bricks arranged in a row from left to right.
  
  The i-th brick from the left (1 \leq i \leq N) has an integer a_i written on
  it.
  
  Among them, you can break at most N-1 bricks of your choice.
  
  Let us say there are K bricks remaining. Snuke will be satisfied if, for each
  integer i (1 \leq i \leq K), the i-th of those brick from the left has the
  integer i written on it.
  
  Find the minimum number of bricks you need to break to satisfy Snuke's desire.
  If his desire is unsatisfiable, print `-1` instead.
samples: [{"input": "3\n    2 1 2", "output": "1\n    \n\nIf we break the leftmost brick, the remaining bricks have integers 1 and 2\nwritten on them from left to right, in which case Snuke will be satisfied.\n\n* * *"}, {"input": "3\n    2 2 2", "output": "-1\n    \n\nIn this case, there is no way to break some of the bricks to satisfy Snuke's\ndesire.\n\n* * *"}, {"input": "10\n    3 1 4 1 5 9 2 6 5 3", "output": "7\n    \n\n* * *"}, {"input": "1\n    1", "output": "0\n    \n\nThere may be no need to break the bricks at all."}]