N, M = map(int, input().split())
List = [int(input()) for _ in range(M)]

P = 1000000007

if N==1:
    print(1)
    
else:
    dp = [0]*(N+1)

    if 1 in List:
        dp[1] = 0
        if 2 in List:
            dp[2] = 0
        else:
            dp[2] = 1
    else:
        dp[1] = 1
        if 2 in List:
            dp[2] = 0
        else:
            dp[2] = 2

    for i in range(2, N):
        if i+1 in List:
            dp[i+1]=0
        else:
            if i in List:
                dp[i+1] = dp[i-1]
            else:
                dp[i+1] = (dp[i]+dp[i-1])
        
    print(dp[N]%P)