import numpy as np
n, m = [int(i) for i in input().split()]
a =[]
d = 1000000007

for i in range(m):
    a1=int(input())
    a.append(a1)

a.append(n+1)
a = np.array(a)
#print(a)

if 1 in a[1:]-a[:-1]:
    print(0)

else:
    dp = [0]*1000001
    dp[1]=1
    dp[2]=1
    for i in range(3,len(dp)):
        dp[i]=dp[i-1]+dp[i-2]
        #dp[i]=dp[i]%d

    ans = []
    pre = 0
    for i in range(len(a)):
        if i == 0:
            ans.append(a[i]-pre)
        else:
            ans.append(a[i]-pre-1)
        pre = a[i]

    #print(ans)
    x = 1
    for i in ans:
        x = x*dp[i]%d
    print(x)