def Fib(n):
    a,b = 1,1
    if n == 1:
        return 1
    elif n == 2:
        return 1
    else:
        for i in range(n-2):
            a,b = b,a+b
        return b
    
n,m = map(int,input().split())
start = []
for i in range(m):
    start.append(int(input()))

if start == []:
    print(Fib(n))
else:
    pstart = [-1]+start+[n+1] #スタートとゴールを追加
    newlist = [] #距離のリスト
    for j in range(len(pstart)-1):
        newlist.append(pstart[j+1]-pstart[j]) #障害物同士の距離を測る
    if 1 in newlist[1:len(newlist)-1]:
                 print(0)
    else: #ちゃんと距離が出そうなとき
        ans = 1
        #print(newlist)
        for w in newlist:
            #print(Fib(w-1))
            #print(ans)
            ans = (ans*Fib(w-1))%1000000007
        print(ans)         