N,M=map(int,input().split())
A=[-1]+[int(input()) for i in range(M)]+[N+1]
res=1
for i in range(1,len(A)):
  steps=A[i]-A[i-1]-2
  if steps<0:
    patern_nmu=0
  else:
    p,q=1,0
    for j in range(steps):
      p,q=p+q,p
    patern_nmu=p
    res*=patern_nmu
    res%=1000000007
print(res)