#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, k;
  cin >> n >> m >> k;
  int m1 = m;
  int k1 = k;
  int m2 = m;
  int k2 = k;
  int *A = new int[n];
  for (int i = 0; i < n; i++) {
    cin >> A[i];
  }
  sort(A, A + n);
  reverse(A, A + n);
  if (m <= k) {
    cout << 0 << endl;
    return 0;
  }
  int result = 0;
  for (int i = 0; i < n; i++) {
    m -= A[i];
    k--;
    result++;
    if (m <= k) {
      cout << result << endl;
      return 0;
    }
    if (k <= 0) {
      break;
    }
  }
  bool b1 = false;
  int pol = 0;
  for (int i = 0; i < n; i++) {
    if (b1 == false) {
      m1 -= A[i];
      pol++;
      k1--;
    } else {
      m1 -= A[i] - 1;
      pol++;
    }
    if ((k1 <= 0) && (b1 == false)) {
      b1 = true;
    }
    if (m1 <= k) {
      cout << pol << endl;
      return 0;
    }
  }
  cout << -1 << endl;
  return 0;
}
