import sys
input = sys.stdin.readline
sys.setrecursionlimit(10**9)
n,m=map(int,input().split())

a=[int(input()) for i in range(m)]

def fib(n):
    if n==0:
        return 1
    if n==1:
        return 1
    if n==2:
        return 2
    return fib(n-1)+fib(n-2)

ans=1
check=0
for i in a:
    if i-check==1 and i!=1:
        print(0)
        exit()
    if i-check==1 and i==1:
        check=1
    else:
      ans*= fib(i-check-2)
      check=i
ans*=fib(n-a[-1]-1)
print(ans%((10**9)+7))
