#include <bits/stdc++.h>
using namespace std;
using namespace std::chrono;
int n, m;
long long y;
int map[100100] = {0};
int a[100100];
void search(int x) {
  if (x > n) return;
  if (x == n) y++;
  if (map[x] == 1) return;
  search(x + 1);
  search(x + 2);
}
int main() {
  scanf("%d", &n);
  scanf("%d", &m);
  for (int i = 0; i < m; i++) {
    scanf("%d", &a[i]);
    map[a[i]] = 1;
  }
  search(0);
  printf("%d", y / 1000000007);
}
