n,m = map(int,input().split())
a = set([int(input()) for _ in range(m)])
print(a)
dp = [0] * (n+1)
dp[0] = 1
for i in range(1,n+1):
  dp[i]=(dp[i-1]+dp[i-2])%(10**9+7)
  if i in a:dp[i]=0
print(dp[n])