#include <bits/stdc++.h>
using namespace std;
queue<int> q;
int main() {
  int n, m, k, count, aux, t;
  vector<int> d(50);
  cin >> n >> m >> k;
  for (int i = 0; i < n; i++) cin >> d[i];
  sort(d.begin(), d.end(), greater<int>());
  q.push(k);
  aux = k;
  t = count = 0;
  for (int i = 0; aux < m && i < n; i++, count++) {
    aux--;
    if (!t) {
      t = q.front();
      q.pop();
    }
    aux += d[i];
    q.push(d[i]);
  }
  cout << ((aux >= m) ? count : -1) << endl;
  return 0;
}
