#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<int, int>;
template <class T>
bool chmax(T& a, const T& b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
bool chmin(T& a, const T& b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}
const ll INF = 1LL << 60;
const int mod = 1000000007;
struct mint {
  ll x;
  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++() {
    if ((x++) >= mod) x -= mod;
    return *this;
  }
  mint& operator-=(const mint a) {
    if ((x += mod - a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator--() {
    if ((x += mod - 1) >= mod) x -= mod;
    return *this;
  }
  mint& operator*=(const mint a) {
    (x *= a.x) %= mod;
    return *this;
  }
  mint operator+(const mint a) const {
    mint res(*this);
    return res += a;
  }
  mint operator-(const mint a) const {
    mint res(*this);
    return res -= a;
  }
  mint operator*(const mint a) const {
    mint res(*this);
    return res *= a;
  }
  mint pow(ll t) const {
    if (!t) return 1;
    mint a = pow(t >> 1);
    a *= a;
    if (t & 1) a *= *this;
    return a;
  }
  mint inv() const { return pow(mod - 2); }
  mint& operator/=(const mint a) { return (*this) *= a.inv(); }
  mint operator/(const mint a) const {
    mint res(*this);
    return res /= a;
  }
};
mint dp[100010];
int main() {
  int n, m;
  cin >> n >> m;
  priority_queue<int, vector<int>, greater<int>> pq;
  for (ll i = 0; i < (ll)(m); i++) {
    int a;
    cin >> a;
    pq.push(a);
  }
  for (ll i = 0; i < (ll)(100010); i++) dp[i] = 0;
  dp[0] = 1;
  int broken = pq.top();
  pq.pop();
  for (int i = 1; i <= n; i++) {
    if (i == broken) {
      if (!pq.empty()) broken = pq.top();
      pq.pop();
      continue;
    }
    dp[i] += dp[i - 1];
    if (i >= 2) dp[i] += dp[i - 2];
  }
  cout << dp[n].x << endl;
  return 0;
}
