#include <bits/stdc++.h>
#include<algorithm>
#include<math.h>
#include<string>
#include<iostream>
#include<vector>
#include<cstdlib>
using namespace std;
 
template <class T> using V = vector<T>;

template<class T> inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

const long long INF = 1LL << 60;
 
using ll = long long;
using db = double;
using st = string;
using ch = char;
using bl = bool;
using vll = V<ll>;
using vpll =V<pair<ll,ll>>;
using vst = V<st>;
using vdb = V<db>;
using vch = V<ch>;
using vbl = V<bl>;
 
 
#define FOR(i,a,b) for(ll i=(a);i<(b);i++)
#define rFOR(i,a,b) for(ll i=(a);i>(b);i--)
#define oFOR(i,a,b) for(ll i=(a);i<(b);i+=2)
#define bgn begin()
#define en end()
#define SORT(a) sort((a).bgn,(a).en)
#define REV(a) reverse((a).bgn,(a).en)
#define M(a,b) max(a,b)
#define rM(a,b) min(a,b)
#define fi first
#define se second
#define sz size()
#define gcd(a,b) __gcd(a,b)
#define co(a) cout<<a<<endl;
#define ci(a) cin>>a;
 
 
ll sum(ll n) {
  ll m=0;
  FOR(i,0,20){
    m+=n%10;
    n/=10;
    if(n==0){
      break;
    }
  }
  return m;
}
 
 
ll combi(ll n,ll m) {
  ll ans=1;
  rFOR(i,n,n-m){
    ans*=i;
  }
  FOR(i,1,m+1){
    ans/=i;
  }
  return ans;
}
 
 
ll lcm(ll a,ll b){
  ll n;
  n=a/gcd(a,b)*b;
  return n;
}
 
 
/****************************************\
| Thank you for viewing my code:)        |
| Written by RedSpica a.k.a. RanseMirage |
| Twitter:@asakaakasaka                  | 
\****************************************/
 
 
signed main() {
  
  ll n,m;
  ci(n>>m);
  vll A(m);
  FOR(i,0,m){
    ci(A[i])
  }
  vll dp(1001000);
  ll now=0;
  ll ans=1;
  dp[0]=1;
  
  if(A[now]==1){
    dp[1]=0;
    now++;
  }
  else{
  dp[1]=1;
  }
  
  FOR(i,2,n+1){
    if(A[now]==i){
      now++;
      dp[i]=0;
    }
    else{
      dp[i]+=dp[i-1]+dp[i-2];
    }
    
    if(now==m){
      now--;
    }
    dp[i]%=1000000007;
  }
  co(dp[n])
}
