import strutils, sequtils, algorithm

var
  N = stdin.readLine.parseInt
  a = stdin.readLine.split.map parseInt
  cnt_S = int.high
  cnt_L = int.low

if a != a.sorted(cmp):
  for a_i in a:
    if a_i == 1: break
    cnt_S = min(cnt_S, a_i)

  for a_i in a.reversed:
    if a_i == N: break
    cnt_L = max(cnt_L, a_i)

  echo max(cnt_L, N - cnt_S)
else:
  echo 0