#include<bits/stdc++.h>
using namespace std;
#define int long long
const int N=1e5+10,P=1000000007;
int a[N],dp[N];bool v[N];
signed main()
{
	int n,m;scanf("%lld%lld",&n,&m);memset(v,0,sizeof v);
	for(int i=1;i<=m;i++)scanf("%lld",&a[i]),v[a[i]]=1;
	if(v[0]==0)dp[0]=1;if(v[1]==0)dp[1]=1;
	for(int i=2;i<=n;i++)if(!v[i])
		dp[i]=(dp[i-1]+dp[i-2])%P;
	printf("%lld\n",dp[n]);return 0;
}