def inputs(num_of_input):
    ins = [input() for i in range(num_of_input)]
    return ins


def solve(inputs):
    [N, M] = list(map(lambda x: int(x), inputs[0].split()))
    broke_steps = list(map(lambda x: int(x), inputs[1:]))

    prev = broke_steps[0]
    for broke_step in broke_steps[1:]:
        if broke_step - prev == 1:
            return 0

    SSSS = 1000000007

    patterns = [1]
    for i, step in enumerate(range(1, N + 1)):
        if step in broke_steps:
            ap = 0
        elif i == 0:
            ap = 1
        else:
            ap = (patterns[i] + patterns[i - 1]) % SSSS
        patterns.append(ap)

    return patterns[-1]


if __name__ == "__main__":
    first = input()
    [N, M] = list(map(lambda x: int(x), first.split()))
    inputs_str = inputs(M)
    inputs_str.insert(0, first)
    ret = solve(inputs_str)
    print(ret)
