#include <bits/stdc++.h>
using namespace std;
const long long mod = 1000000007;
int cnt = 0;
void step_by_step(int x, int n, int m, vector<int> a) {
  if (x == n) {
    cnt++;
  }
  bool c = true;
  for (int i = 0; i < m; i++) {
    if (x == a.at(i)) {
      c = false;
      break;
    }
  }
  if (c == true && x < n) {
    step_by_step(x + 1, n, m, a);
    step_by_step(x + 2, n, m, a);
  }
}
int main() {
  int N, M;
  cin >> N >> M;
  vector<int> a(M);
  for (int i = 0; i < M; i++) cin >> a.at(i);
  step_by_step(0, N, M, a);
  cout << cnt % mod << endl;
  return 0;
}
