new_contents: #!/bin/python
  
  def bsearch(L, target):
      lo = 0
      hi = len(L)
      while lo < hi:
          mid = lo + (hi - lo) // 2
          if L[mid] > target:
              hi = mid
          elif L[mid] < target:
              lo = mid + 1
          else:
              return mid
      return -1        
  
  target = int(raw_input())
  size = int(raw_input())
  L = [int(value) for value in raw_input().split()]
  index = bsearch(L, target)
  print index
  
subject: Create solution.py