n,m = map(int,input().split())
a =  [int(input()) for i in range(m)]

dp =[0]*(n+1)
if 0 in a:
    dp[0] =0
else:
    dp[0]=1

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

for i in range(2,n+1):

    if dp[i-1]==dp[i-2]==0:break

    dp[i] = (dp[i-2]+dp[i-1])

    if i in a:
        dp[i] = 0

print(dp[-1]%1000000007)