#include <bits/stdc++.h>
using namespace std;
bool comp(int a, int b) { return a > b; }
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n, m, k;
  cin >> n >> m >> k;
  int arr[n];
  for (int i = 0; i < (n); ++i) {
    cin >> arr[i];
  }
  sort(arr, arr + n, comp);
  int c = k;
  int i = 0;
  while (c < m) {
    c--;
    c += arr[i];
    i++;
  }
  if (i <= n)
    cout << i;
  else
    cout << "-1";
  return 0;
}
