n,m= map(int,input().split())

if n==1:
    print(1)
else:
    dp=[1]*(n+1)
    a=[1]*n
    a[int(input())]=0
    if a[0]==0:
        dp[0]=0
    if a[1]==0:
        dp[1]=0
    for i in range(2,n+1):
        dp[i]=(dp[i-1]+dp[i-2])%1000000007
        if a[i]==0:
            dp[i]==0
print(dp[n]%1000000007)