def fib(n):
    a, b = 1, 1
    if n == 1:
        return a
    elif n == 2:
        return b
    else:
        for i in range(n-2):
            a, b = b, a + b
        return b

n,m = map(int,input().split())
a = [int(input()) for i in range(m)]
ans = fib(a[0])
for j in range(1,m):
    if m == 1:
        continue
    elif a[j] == a[j-1]+1:
        ans = 0
    else:
        ans *= fib(a[j]-a[j-1]-1)
ans *= fib(n-a[m-1])
print(ans%1000000007)
