#include <bits/stdc++.h>
using namespace std;
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long long int n, m, k;
  cin >> n >> m >> k;
  if (k >= m) {
    cout << 0;
    return 0;
  }
  vector<long long int> v;
  for (long long int i = 0; i < n; i++) {
    long long int arb;
    cin >> arb;
    v.push_back(arb);
  }
  sort(v.rbegin(), v.rend());
  for (long long int i = 1; i < n; i++) {
    v[i] = v[i] + v[i - 1];
  }
  for (long long int i = 0; i < n; i++) {
    if (v[i] + (k - i - 1) >= m) {
      cout << i + 1;
      return 0;
    }
  }
  cout << -1;
}
