from functools import lru_cache

n, m = map(int, input().split())
a = []
for i in range(m):
  a.append(int(input()))
  
@lru_cache(maxsize=100000)
def comb(n):
  if n in a:
    return 0
  elif n in (0, 1):
    return 1
  else:
    return (comb(n-1) + comb(n-2))

print(comb(n)%(10**9 + 7))