from sys import exit
class Fib:
  def __init__(self):
    self.memo = {}
  def calc(self, n):
    if n == 1 or n == 2:
      self.memo[n] = 1
      return 1
    if n <= 0:
      self.memo[n] = 0
      return 0
    if n in self.memo.keys():
      return self.memo[n]
    self.memo[n] = self.calc(n - 1) + self.calc(n - 2)
    return self.memo[n]

N, M = map(int, input().split())
ans = 1
mod = 10 ** 9 + 7
pre = -1
for i in range(M):
  a = int(input())
  if a == 1:
    pre = a
    continue
  if a == pre + 1 and pre != 0:
    print(0)
    exit()
  ans *= Fib().calc(a - pre - 1) % mod
  pre = a
ans *= Fib().calc(N - pre) % mod
print(ans % mod)