def main():
  N, M= map(int, input().split())
  a =[str(input()) for _ in range(M)]
  DP = [0]*(N+1)
  num = 1000000007
  DP[0] = 1
  for i in range(N):
    if str(i) in a:
      DP[i] = (DP[i-1] + DP[i-2]) % num
  print(DP[-1]%num)
if __name__ == "__main__":
    main()