n,m = map(int,input().split())
a = []
mod = 10**9+7
d = [0 for i in range(n+1)]
d[0] = 1
d[1] = 1
d[2] = 2
for i in range(3,n+1):
    d[i] = d[i-1] + d[i-2]
d.append(0)
if m != 0:
    for i in range(m):
        b = int(input())
        a.append(b)
    ans = 1
    if a[0] == 1:
        ans = 1
    else:
        ans = ans*d[a[0]-1]%mod
    for i in range(m-1):
        ans = ans*d[a[i+1]-a[i]-2]%mod
    ans = ans*d[n-a[m-1]-1]%mod
else:
    ans = d[n]
print(ans)