# ABC_129 C

def stairs(n, a):
    dp = [0 for _ in range(n+1)]
    dp[0] = 1
    if 1 not in a:
        dp[1] = 1
    for i in range(2, n+1):
        if i in a:
            continue
        dp[i] = dp[i-1]
        dp[i] += dp[i-2]

    result = dp[n] % 1000000007

    print(result)


n, m = list(map(int, input().split()))
a = [int(input()) for _ in range(m)]

if __name__ == '__main__':
    stairs(n, a)