n,m=map(int,input().split())
a=[-1]
for i in range(m):
    s=int(input())
    a.append(s)  
a.append(n+1)
if 1 in a:
    a=a[1:]
if n-1 in a:
    a=a[:-1]
b=[]
for i in range(len(a)-1):
    b.append(a[i+1]-a[i]-2)
l=[0,1,2]
for i in range(3,n+1):
    l.append(l[i-2]+l[i-1])
ans=1

for i in range(len(b)):
    if b[i]<0:
        print(0)
        break
    else:
        ans*=l[b[i]]%1000000007
else:
    #print(a,b,l)
    print(ans%1000000007)
