MOD = 1000000007
# f(x) = f(x - 1) + f(x - 2)の場合のdp
def f_dp(x, a):
    dp = [0 for i in range(x + 1)]
    dp[0] = 1
    if 1 not in a:
        dp[1] = 1
    for i in range(2, x + 1):
        if i not in a:
            dp[i] = dp[i - 1] + dp[i -2]
    return dp[n] % MOD

if __name__ == "__main__":
    n, m = map(int, input().split())
    a = [int(input()) for i in range(m)]

    dp = f_dp(n, a)
    print(dp)