n,m=map(int,input().split())
a=int(input())
b=1
s=[1]*(n+1)
for i in range(1,n+1):
    if i!=a:
        if i-2>=0:
            s[i]=(s[i-1]+s[i-2])%1000000007
        else:
            s[i]=s[i-1]%1000000007
    elif b!=m:
        s[i]=0
        a=int(input())
        b+=1
    else:
        s[i]=0
print(s[n])
        
