import sys
input = sys.stdin.readline


def fib(n):
    '''f(n)=f(n-1)+f(n-2)'''
    a, b = 0, 1
    for _ in range(n-1):
        a, b = b, a+b
    return b


n, m = map(int, input().split())
mod = 10**9+7
a = [int(input()) for _ in range(m)]
if not a:
    ans = fib(n+1)
else:
    ans = fib(a[0])*fib(n-a[m-1]) % mod
    for i in range(m-1):
        if a[i+1]-a[i] == 1:
            ans = 0
            break
        ans = ans * fib(a[i+1]-a[i]-1) % mod

print(ans)
