# coding: utf-8
import os
import time
import re
import math


def main():
    N,M=map(int,input().split())
    A=[int(input()) for  a in range(M)] #a (1段~N-1段)
    start=time.time();#
    memo=[0]*(N+1)
    memo[0]=1
    ban=[False]*(N+1)
    for a in M:
        ban[a]=True
    mod=1000000007
    print(ban)
    for a in range(1,N+1):
        if ban[a]:
            memo[a]=0
        else:
            if a>1:
                memo[a]=(memo[a-1]+memo[a-2])%mod
            else:
                memo[a]=1



    print(memo[-1]%mod)
    #print("{}ms".format(math.floor(time.time()*1000-start*1000)))#


main()
