import sys
input=sys.stdin.readline

n,m = map(int, input().split())
a = []
for i in range(m):
    a.append(int(input()))
if len(a) >= 2:
    for i in range(m-1):
        if a[i]+1 == a[i+1]:
            print(0)
            exit()
def fib(n):
    a, b = 1, 0
    for _ in range(n):
        a, b = a + b, a
    return b

tmp = 0
ans = 1
for i in range(len(a)):
    ans *= fib(a[i]-tmp-1)
    tmp = a[i]+1
if tmp < n:
    ans *= fib(n-tmp)
print(ans%(10**9+7))
