mod = 1000000007
n, m = map(int, input().split())
dat_m = []
dp = []
for i in range(n + 1):
    dp.append([0] * (n + 1))
for i in range(m):
    dat_m.append(int(input()))
dp[0][0] = 1
#print(dp[0][0])
for i in range(1, n + 1):
    #dp[i][:i-1] = dp[i-1][:i - 1]
    dp[i][i-1] = dp[i - 1][i - 1]
    dp[i][i] = dp[i - 1][i - 1]

    if i > 1:
        dp[i][i] += dp[i - 1][i - 2]
        dp[i][i-2] = dp[i - 1][i - 2]

    if i in dat_m:
        dp[i][i] = 0

    dp[i][i] = dp[i][i] % mod

import pprint
print(dp[n][n])
#pprint.pprint(dp)