N, M=map(int, input().split())
mod=10**9+7
pre=-1
hole=[]
for i in range(M):
  a=int(input())
  hole.append(a-1-pre)
  pre=a
hole.append(N-pre)

  

dp=[0]*(N+3)
dp[1]=1
dp[2]=1
for i in range(3,N+3):
  dp[i]=(dp[i-1]+dp[i-2])%mod
if len(hole)==1:
  print(dp[N+1])
  
#print(dp)
#print(hole)
ans=1
for h in hole:
  ans*=dp[h]
  ans%=mod
  
print(ans)