#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
const long long mod2 = 998244353;
const long long N = 1e5 + 5;
const long long N2 = 1e6 + 5;
long long sum() { return 0; }
template <typename... Args>
long long sum(long long a, Args... args) {
  return a + sum(args...);
}
void err(istream_iterator<string> it) {}
template <typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
  cerr << *it << " = " << a << endl;
  err(++it, args...);
}
istream &operator>>(istream &in, vector<long long> &v) {
  for (long long i = 0; i < v.size(); i++) in >> v[i];
  return in;
}
ostream &operator<<(ostream &out, vector<long long> &v) {
  for (long long i = 0; i < v.size(); i++) out << v[i] << ' ';
  cout << '\n';
  return out;
}
void solve() {
  long long n, m, k;
  cin >> n >> m >> k;
  vector<long long> v(n);
  cin >> v;
  sort(v.rbegin(), v.rend());
  for (long long i = 0; i < n; i++) {
    if (k >= m) {
      cout << i;
      return;
    }
    k += v[i] - 1;
  }
  if (k >= m)
    cout << n;
  else
    cout << -1;
}
int32_t main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long t = 1;
  for (long long tc = 1; tc < t + 1; tc++) {
    solve();
  }
}
