import numpy as np
N,M=map(int,input().split())
A=[]
for _ in range(M):
    A.append(int(input()))

mod=10**9+7

dp=np.zeros(N+1)
dp[0]=1
for i in range(1,N+1):
    if i in A:
        dp[i]=0
    else:
        if i==1:
            dp[i]=dp[i-1]
        else:
            dp[i]=dp[i-1]+dp[i-2]
            dp[i]=dp[i]%mod
dp[N]=dp[N]%mod
print(int(dp[N]))