n, m  = map(int,input().split())
a = [int(input()) for _ in range(m)]

MOD = 10**9+7

dp = [0]*(n+1)
ng = [False]*(n+1)
for i in a:
    ng[a] = True
    
dp[0] = 1
if not ng[1]:
    dp[1] = 1
for i in range(2, n+1):
    if a[i]:
        continue
    else:
        dp[i] = (dp[i-1] + dp[i-2]) % MOD
print(dp[n])