N, M = list(map(int, input().split()))
a = []
for i in range(0, M):
    a.append(int(input()))
a.sort()
T = 10 ** 9 + 7

r = [0 for _ in range(N + 1)]
r[0] = 1
r[1] = 1


def fib(n):
    if r[n] > 0:
        return r[n]
    else:
        return fib(n - 1) + fib(n - 2)


for i in range(0, M - 1):
    if a[i] + 1 == a[i + 1]:
        print(0)
        break
else:
    now = 0
    c = 1
    for i in range(0, M):
        c *= fib(a[i] - now - 1) % T
        c %= T
        now = a[i] + 1
    c *= fib(N - now)
    print(c % T)