n,m = map(int,input().split())
a = [int(input()) for _ in range(m)]
num = 10**9+7
count = [0]*(n+1)
count[0] = 1
count[1] = 1 if 1 not in a else 0
for i in range(2,n+1):
  if i not in a: count[i] = count[i-1] + count[i-2]
  count[i] = count[i]%num
print(count[n])
