mod = 10**9+7

N,M = [int(x) for x in input().split()]
a = [int(input()) for _ in range(M)]
dp = [0 for _ in range(N+1)]
dp[0] = 1
for i in range(N+1):
    if(i in a):
        continue
    if(i<N-1):
        if(i+2 not in a):
            dp[i+2]+=dp[i]
    if(i<N):
        if(i+1 not in a):
            dp[i+1]+=dp[i]
print(dp[-1]%mod)
