
n,m = map(int,input().split())
b = [True] * n
for i in range(m):
    x = int(input())
    b[x-1] = False

dp = [0] * n
if(n == 1):
    print(1)
if(b[0]):
    dp[0] = 1
    if(b[1]):dp[1] = 2
else:
    if(b[1]):dp[1] = 1

for i in range(2,n):
    if(b[i]):
        dp[i] = dp[i-1] + dp[i-2]
        dp[i] %= 1000000007
print(dp[-1])