def solve(N, M, A):
    MOD = 10**9 + 7
    A = set(A)
    if N == 1:
        return 1

    dp = [0] * (N+1)
    dp[0] = 1
    dp[1] = 1 if 1 not in A else 0
    for i in range(2, N+1):
        if i in A:
            dp[i] = 0
        else:
            dp[i] = (dp[i-2] + dp[i-1]) % MOD
    return dp[-1]


N, M = map(int, input).split())
A = [int(input()) for _ in range(M)]
ans = solve(N, M, A)
print(ans)

