n = int(input())
l = list(map(int, input().split()))

for i in range(len(l), 0, -1):
  try:
    if not abs(l[i]-l[i-1]) % 2 == 0:
      try:
        if not l[i-2] == l[i-1]-1:
          l.pop(i)
          l.pop(i-1)
      except IndexError:
        continue
  except IndexError:
    continue

print(len(l))