n, m = map(int, input().split())
mod = 1000000007
a = [True] * (n + 1)
for i in range(m):
    a[int(input())] = False
dp = [0] * (n + 1)
dp[0] = 1

dp[1] = dp[0] if a[1] else 0

for i in range(2, n + 1):
    if a[i]:
        dp[i] = (dp[i - 1] + dp[i - 2]) % mod

print(dp)