#include <bits/stdc++.h>
using namespace std;
int n, m, k, arr[55], s, c, i;
int main() {
  for (cin >> n >> m >> k; i < n; i++) cin >> arr[i];
  sort(arr, arr + n, greater<int>());
  if (k >= m) {
    cout << 0 << endl;
    return 0;
  }
  i = 0;
  while (k-- && s < m && i < n) {
    s += arr[i++], c++, s += k;
    if (s >= m) return (cout << c << endl, 0);
    s -= k;
  }
  if (s >= m)
    cout << c << endl;
  else if (i < n) {
    while (i < n && s < m) s += arr[i++], s--, c++;
  }
  if (s >= m)
    cout << c << endl;
  else
    cout << -1 << endl;
}
