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