#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
signed main() {
  long long n, k;
  cin >> n >> k;
  vector<long long> oks(n + 1, true);
  long long a;
  cin >> a;
  oks[a] = false;
  vector<long long> dp(n + 1);
  dp[0] = 1;
  for (long long now = 0; now < n; now++) {
    for (long long next = now + 1; next <= min(n, now + 2); next++) {
      if (oks[next]) {
        dp[next] += dp[now];
        dp[next] %= mod;
      }
    }
  }
  cout << dp[n] << endl;
}
