import sys
def I(): return int(sys.stdin.readline().rstrip())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
N,M = LI()
a = [I() for _ in range(M)]
dp = [0]*(N+1) #1_indexed
dp[0] = 1
dp[1] = 0 if 1 in a else 1
for i in range(2,N+1):
    if i in a:
        dp[i] = 0
        continue
    dp[i] = dp[i-1]+dp[i-2]
    dp[i] %= 10**9+7
print(dp[-1])
