#https://atcoder.jp/contests/abc129/tasks/abc129_c

def dp1(n,a):
    dp=[0]*(n+1)
    dp[0]=1
    if 1 not in a:
        dp[1]=1
    if n==1:
        return dp[1]
    else:
        for i in range(2,n+1):
            if i not in a:
                dp[i]=dp[i-1]+dp[i-2]    
    return dp[n]

def main():
    n, m= map(int, input().split())
    a = [int(input()) for _ in range(m)]    
    print(dp1(n,a)%1000000007)

main()