d = {0:1, 1:1, 2:2}
def countcombi(n):
    if n in d:
        return d[n]
    else:
        d[n] = countcombi(n-1)+countcombi(n-2)
        return d[n]
N, M = list(map(int,input().rstrip().split()))
a_now = 0
a_before = 0
ans = 1
for _ in range(M):
    a_now = int(input().rstrip())
    if a_now-a_before == 0 and a_before != 0:
        print(0)
        break
    ans = (ans * countcombi(a_now-a_before-1)) % 1_000_000_007
    a_before = a_now + 1
else:
    a_now = N
    ans = (ans * countcombi(a_now-a_before)) % 1_000_000_007
    print(ans)