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

    ansls = [0]*(n+1)

    if 0 not in a:
        ansls[0] = 1
    if 1 not in a:
        ansls[1] = 1

    for i in range(2, n+1):
        if i not in a:
            ansls[i] = (ansls[i-2] + ansls[i-1])%(10**9 + 7)
    
    print(ansls[-1])
    
if __name__ == "__main__":
    main()
