#include <bits/stdc++.h>
#define repz(i, z, n) for (decltype(n) i = (z); i < (n); i++)
#define rep(i, n) for (decltype(n) i = 0; i < (n); i++)

#define REPZ(i, z, n) for (decltype(n) i = (z); i <= (n); i++)
#define REP(i, n) for (decltype(n) i = 0; i <= (n); i++)
#define ALL(v) v.begin(), v.end()
#define SIZE(v) ((ll)(v).size())
#define MAX(v) (*max_element(ALL(v)))
#define MIN(v) (*min_element(ALL(v)))
#define INF 1000000000000  // 1E+12

// 略
#define PB push_back
#define F first
#define S second
#define MP make_pair
#define READ cin >>
#define PRINT cout <<
#define PYES cout << "YES" << endl
#define pyes cout << "Yes" << endl
#define POK cout << "OK" << endl
#define PNO cout << "NO" << endl
#define pno cout << "No" << endl
#define PNG cout << "NG" << endl
#define ret return 0

using namespace std;

// デバッグ用
void debug_out() { cout << endl; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cout << H << " ";
  debug_out(T...);
}

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

#ifdef _DEBUG
#define debug(...) debug_out(__VA_ARGS__)
#else
#define debug(...)
#endif

// typedef
typedef long long ll;
typedef unsigned long long ul;
typedef long double ld;
typedef pair<ll, ll> pl;

// const
// 円周率
const ld pi = acos(-1);
// mod用
// 1E+9 +7
const ll mod = (ll)1e+9 + 7;
// 1s間で可能なループ回数2E+8回
// ll        最大値2147483647         〜2E+9
// long long  最大値9223372036854775807〜9E+18
// 総和accumulate
// 単純リストvector<type> push_back
// 連想配列map<key,value> insert,
// 集合set<type>
// pair キーとバリューを格納 firstとsecondでアクセス
// 小数点指定 cout << fixed << setprecision(15) << endl;
// to_string<->stoi
// stoll(longlong)
// stod(double)
// deep copy v1->v2 copy(v1.begin(), v1.end(), back_inserter(v2) );
// 大文字65-90(-32)
// 小文字97-122(+32)
//  priority_queue<pair<ll, ll>, vector<pair<ll, ll>>, greater<pair<ll, ll>>>
//  ba;
struct mint {
  ll x;  // typedef long long ll;
  mint(ll x = 0) : x((x % mod + mod) % mod) {}
  mint operator-() const { return mint(-x); }
  mint &operator+=(const mint a) {
    if ((x += a.x) >= mod) x -= mod;
    return *this;
  }
  mint &operator-=(const mint a) {
    if ((x += mod - a.x) >= mod) x -= mod;
    return *this;
  }
  mint &operator*=(const mint a) {
    (x *= a.x) %= mod;
    return *this;
  }
  mint operator+(const mint a) const { return mint(*this) += a; }
  mint operator-(const mint a) const { return mint(*this) -= a; }
  mint operator*(const mint a) const { return mint(*this) *= a; }
  mint pow(ll t) const {
    if (!t) return 1;
    mint a = pow(t >> 1);
    a *= a;
    if (t & 1) a *= *this;
    return a;
  }

  // for prime mod
  mint inv() const { return pow(mod - 2); }
  mint &operator/=(const mint a) { return *this *= a.inv(); }
  mint operator/(const mint a) const { return mint(*this) /= a; }
};
istream &operator>>(istream &is, const mint &a) { return is >> a.x; }
ostream &operator<<(ostream &os, const mint &a) { return os << a.x; }
signed main() {
  // faster
  // C言語流の入出力は使用できない
  ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  ll n, m;
  cin >> n >> m;
  vector<bool> isbreak(n + 1, false);
  rep(i, m) {
    ll temp;
    cin >> temp;
    isbreak[temp] = true;
  }
  vector<mint> dp(n + 1, 0);
  dp[0] = 1;
  rep(i, n) {
    if (i + 2 <= n and !isbreak[i + 2]) dp[i + 2] += dp[i];
    if (i + 1 <= n and !isbreak[i + 1]) dp[i + 1] += dp[i];
  }
  cout << dp[n] << endl;
  ret;
}


Measured memory_bytes: 3972