#include "bits/stdc++.h"
using namespace std;
#define ll long long
#define endl '\n'
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define rep2(i,a,b) for(int i=int(a);i<int(b);i++)
#define pb emplace_back
#define all(x) (x).begin(),(x).end()
ll mod=1e9+7;
ll mod2=998244353;
const int INF=1e9;

signed main(){
	ll n,m;
    cin>>n>>m;
    vector<ll> a(n,0);
    rep(i,n){
        ll b;
        cin>>b;
        a[b]=1;
    }
    vector<ll> dp(n+2,0);
    dp[0]=1;
    rep(i,n){
        dp[i]%=mod;
        if(a[i+1]!=1)dp[i+1]+=dp[i];
        if(a[i+2]!=1)dp[i+2]+=dp[i];
    }
    cout<<dp[n]%mod<<endl;
}

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