import sys

sys.setrecursionlimit(1000000)

N, M = map(int, input().split())
oks = [True] * (N+1)
a = [int(input()) for _ in range(M)]
for i in a:
    oks[i] = False
dp = [0] * (N+1)
if oks[1]:
    dp[1] = 1
if oks[2]:
    print("a")
    dp[2] = 1
for i in range(3, N+1):
    if oks[i]:
        dp[i] = int((dp[i-1] + dp[i-2]) % (1e9+7))


print(dp[N])