def fib(n):
    a1 = 2
    a2 = 1 
    if n==2:
        return 2
    elif n==1:
        return 1
    else:
        count = 1
        for i in range(n-2):
            count = a1 + a2
            a2 = a1
            a1 = count
        return count
        
N,M = list(map(int,input().split()))
ans = 1
z = False

if M == 0:
    ans *= fib(N)
    print(ans) 
else:
    a = [int(input()) for _ in range(M)]

    for i in range(M):
        if i != 0:
            if a[i]-a[i-1] != 1:
                ans *= fib(a[i]-a[i-1]-2)
            else:
                z = True
                break
        else:
            ans *= fib(a[i]-1)

    ans *= fib(N-a[-1]-1)

    if z:
        print(0)
    else:
        print(str(ans%1000000007))