#include <bits/stdc++.h>
using namespace std;
// #include <bits/stdtr1c++.h>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
// using namespace __gnu_pbds;


/*#pragma GCC optimize("Ofast,no-stack-protector")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC optimize("unroll-loops")*/

/// Typedef
typedef long long           ll;
typedef unsigned long       ul;
typedef unsigned long long  ull;
typedef vector<int>         vi;
typedef vector<ll>          vl;
typedef vector<vi>          vvi;
typedef vector<ll>          vll;
typedef pair<int,int>       pii;
typedef pair<ll,ll>         pll;

#define pb                  push_back
#define ppb                 pop_back
#define MP                  make_pair
#define ff                  first
#define ss                  second
#define sf                  scanf
#define pf                  printf
#define loop(i, y)          for(int i=0; i<int(y); i++)
#define FOR(i, x, y)        for(int i=int(x); i<int(y); i++)
#define ROF(i, x, y)        for(int i=int(x); i>=int(y); i--)
#define all(c)              c.begin(), c.end()
#define sz(c)               int(c.size())
#define clr(x, y)           memset(x, y, sizeof(x))
#define si(x)               scanf("%d", &x)
#define sii(x, y)           scanf("%d %d", &x, &y)
#define siii(x, y, z)       scanf("%d %d %d", &x, &y, &z)
#define sl(x)               scanf("%lld", &x)
#define sll(x, y)           scanf("%lld %lld", &x, &y)
#define slll(x, y, z)       scanf("%lld %lld %lld", &x, &y, &z)
template <class T> inline T bigMod(T p,T e,T M){ ll ret = 1; for(; e > 0; e >>= 1){ if(e & 1) ret = (ret * p) % M; p = (p * p) % M; } return (T) ret;}
template <class T> inline T modInverse(T a,T M){return bigMod(a,M-2,M);}
template <class T> inline T gcd(T a,T b){if(b==0)return a;return gcd(b,a%b);}
template <class T> inline T lcm(T a,T b) {a=abs(a);b=abs(b); return (a/gcd(a,b))*b;}
template <class T> inline string int2String(T a){ostringstream str; str<<a; return str.str();}
template <class T> inline T string2int(string a){stringstream str(a); T b; str>>b; return b;}


#define MAX                 200005
#define MOD                 1000000007
#define base                1000000007
#define eps                 1e-9
#define INF                 1llu<<61    // 2,305,843,009,213,693,952
#define inf                 1<<29       // 536,870,912
#define PI                  acos(-1.0)  // 3.1415926535897932
// #define INF              0x3f3f3f3f3f3f3f3f
// #define inf              0x3f3f3f3f

int ara[MAX],n;
ll dp[MAX];
bool vis[MAX];
ll solve(int  pos){
    //cout<<pos<<" ";
    if(pos>n)return 0;
    if(pos>=n){
      //  cout<<pos<<endl;
        return 1%MOD;
    }
    if(dp[pos]!=-1)return dp[pos];
    ll res = 0;
    if(!vis[pos+1]){
       res = (res%MOD + solve(pos+1)%MOD)%MOD ;
    }
    if(!vis[pos+2]){
       res = (res%MOD + solve(pos+2)%MOD)%MOD ;
    }
    return dp[pos]=res%MOD;
}
int main(){
    #ifdef VAMP
        clock_t tStart = clock();
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    #endif
    int m;
    sii(n,m);
    FOR(i,0,m){
        si(ara[i]);
        vis[ara[i]]=1;
    }
    sort(ara,ara+m);
    FOR(i,0,m-1){
        if(ara[i]+1 == ara[i+1]){
            cout<<0<<endl;
            return 0;
        }
    }
    ll ans=0;
    clr(dp,-1);
    //solve(0);
    cout<<solve(0)%MOD<<endl;
    #ifdef VAMP
       printf("\n>>Runtime: %.10fs\n", (double) (clock() - tStart) / CLOCKS_PER_SEC);
    #endif

    return 0;
}

Measured memory_bytes: 4992