import sys
sys.setrecursionlimit(10 ** 7)

N, M = map(int, input().split())
A = [int(input()) for _ in range(M)]

MOD = 10 * 9 + 7
dp = [0] * (N + 1)
dp[0] = 1
for i in range(1, N+1):
    if i not in A:
        dp[i] = (dp[i-1] + dp[i-2]) % MOD
print(dp[N])