n,m=map(int,input().split())

a=[1,1]
for i in range(2,10000):
    a.append((a[i-1]+a[i-2])%1000000007)
bad=[]
for i in range(m):
    bad.append(int(input()))
num=[]
before=0
bad_flag=0
# print(bad)
for i in range(len(bad)):
    nxt=bad[i]-before-1
    if nxt==-1:
        bad_flag=1
        break
    num.append(nxt)
    before=bad[i]+1
num.append(n-bad[len(bad)-1]-1)
if bad_flag:
    print(0)
else:
    ans=0
    last=1
    for i in num:
        # print(num,a[i])
        ans=a[i]*last
        last=ans%1000000007
    print(last)
    