#include <bits/stdc++.h>
using namespace std;
int main() {
  long n, m;
  long long int ans = 1;
  cin >> n >> m;
  vector<long> a(m + 2);
  vector<long> num(n + 1);
  a.at(0) = -1;
  a.at(m + 1) = n + 1;
  for (int i = 1; i < m + 1; ++i) cin >> a.at(i);
  num.at(0) = 0;
  num.at(1) = 0;
  num.at(2) = 1;
  for (int i = 3; i < n + 1; ++i) num.at(i) = num.at(i - 1) + num.at(i - 2);
  for (int i = 1; i < m + 2; ++i) {
    int x = a.at(i) - a.at(i - 1);
    ans *= num.at(x);
    ans = ans % 1000000007;
  }
  cout << ans << endl;
}
