output_description: Print the index of the place where the palace should be built.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
      T A
      H_1 H_2 ... H_N
attempt: """
  半ば強引に二分探査で書いた。
  """
  
  # 入力
  n = int(input())
  t, a = map(int, input().split())
  h = list(map(int, input().split()))
  h_not_sorted = h
  h = sorted(h)
  x = abs((t - a) / 0.006)
  
  # 二分探査
  l = 0
  r = n - 1
  x_index = 0
  while l + 1 != r:
      middle = (l + r) // 2
      if h[middle] == x:
          x_index = middle
          break
      elif h[middle] < x:
          x_index = middle + 1
          l = middle
      else:
          x_index = middle - 1
          r = middle
  
  
  # x_indexが両橋の場合とそれ以外で場合わけ。
  res = abs(a - (t - 0.006 * h[x_index]))
  ans = x_index
  flag_r = True
  flag_l = True
  if x_index == n - 1:
      flag_r = False
  elif x_index == 0:
      flag_l = False
  else:
      pass
  
  # x_indexの両橋と比較。x_indexが際数値でない可能性があるため。
  if flag_r:
      if abs(a - (t - 0.006 * h[x_index + 1])) < res:
          res = abs(a - (t - 0.006 * h[x_index + 1]))
          ans += 1
  if flag_l:
      if abs(a - (t - 0.006 * h[x_index - 1])) < res:
          res = abs(a - (t - 0.006 * h[x_index - 1]))
          ans -= 1
  
  print(h_not_sorted.index(h[ans]) + 1)
  
problem_description: Statement
  
  A country decides to build a palace.
  
  In this country, the average temperature of a point at an elevation of x
  meters is T-x \times 0.006 degrees Celsius.
  
  There are N places proposed for the place. The elevation of Place i is H_i
  meters.
  
  Among them, Princess Joisino orders you to select the place whose average
  temperature is the closest to A degrees Celsius, and build the palace there.
  
  Print the index of the place where the palace should be built.
  
  It is guaranteed that the solution is unique.
samples: [{"input": "2\n    12 5\n    1000 2000", "output": "1\n    \n\n  * The average temperature of Place 1 is 12-1000 \\times 0.006=6 degrees Celsius.\n  * The average temperature of Place 2 is 12-2000 \\times 0.006=0 degrees Celsius.\n\nThus, the palace should be built at Place 1.\n\n* * *"}, {"input": "3\n    21 -11\n    81234 94124 52141", "output": "3"}]