#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll INF = 1LL << 31;
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-=(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;
  }
  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; }
int main() {
  int n, m, a = 0;
  ll dp[100010];
  cin >> n;
  for (int i = 0; i < (int)(n + 10); i++) dp[i] = 0;
  dp[0] = 1;
  cin >> m;
  for (int i = 0; i < (int)(m); i++) cin >> a;
  dp[a] = -1;
  for (int i = 0; i < n; i++) {
    if (dp[i] != -1) {
      if (dp[i + 1] != -1) dp[i + 1] += (dp[i]);
      if (dp[i + 2] != -1) dp[i + 2] += (dp[i]);
      if (dp[i + 1] != -1) dp[i + 1] %= mod;
      if (dp[i + 2] != -1) dp[i + 2] %= mod;
    }
  }
  cout << dp[n] << endl;
}
