n,m=map(int,input().split())
ls=[]
for i in range(m):
    ls.append(int(input()))

dp=[0]*(n+1)
dp[0]=1
dp[1]=0 if 1 in ls else 1
for i in range(2,n+1):
    dp[i]=0 if i in ls else (dp[i-1]+dp[i-2])%(10**9+7)
ans=dp[n]
print(ans)
