#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, k;
  cin >> n >> m >> k;
  int j = 0;
  int w = 0;
  if (m <= k) {
    cout << "0";
    return 0;
  }
  int a[n];
  for (int i = 0; i < n; ++i) {
    cin >> a[i];
    w += a[i];
  }
  if (w - n + k < m) {
    cout << "-1";
    return 0;
  }
  sort(a, a + n);
  while (n) {
    m -= a[n - 1];
    n--;
    j++;
    k--;
    if (m <= k) {
      cout << j;
      return 0;
    }
  }
  cout << j;
}
