inf = input().split()
N = int(inf[0])
M = int(inf[1])
ls = []
for i in range(M):
  a = int(input())
  ls += [a]
step = [0 for i in range(N)]
if 1 not in ls:
  step[0] = 1
if 2 not in ls:
  step[1] = 1 + step[0]
for j in range(2, N):
  if j not in ls:
    step[j] = step[j-1]+step[j-2]
  else:
    step[j] = 0
ans = step[N-1]%(10^9+7)
print(ans)