from collections import deque

def num_way(n):
    memo = [0]*(n+1)

    def _fib(n):
        if n <= 1:
            return n
        if memo[n] != 0:
            return memo[n]
        memo[n] = _fib(n-1) + _fib(n-2)
        return memo[n]

    return _fib(n)

N, M = map(int,input().split())
a = deque([0])
path_poss = 1
ans = 1
for m in range(M):
  start = a.popleft()
  buff = int(input())
  end = buff-1
  if (end-start) <= -1:
    path_poss = 0
    break
  a.append(buff+1)
  ans *= num_way(end-start)
  ans %= 1000000007

if path_poss == 0:
  print(0)
else:
  start = a.popleft()
  end = N
  if (end-start) <= -1:
    path_poss = 0
  if path_poss == 0:
    print(0)
  else:
  	ans *= num_way(end-start)
  	print(ans%1000000007)