fiblist = [0] * 100001
fiblist[0] = 1
fiblist[1] = 1

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

if m == 0:
    print(fiblist[n])
else:
    a = []
    for i in range(m):
        a.append(int(input()))

    d = [a[0]-1]
    for j in range(1,m):
        d.append(a[j]-a[j-1]-2)

    d.append(n-a[m-1]-1)


    for p in range(2,100001):
        fiblist[p] = (fiblist[p-1]+fiblist[p-2]) % 1000000007

#print(d)

    if (-1 in d) or (-2 in d):
        print(0)
    else:
        ans = 1
        for k in range(m+1):
            ans = (ans * fiblist[d[k]]) % 1000000007

        print(ans)
