#include <bits/stdc++.h>
using namespace std;
const int maxN = 100 + 5;
const int mod = 1000 * 1000 * 1000 + 7;
int a[maxN];
int main() {
  ios_base::sync_with_stdio(false);
  int n, m, k;
  cin >> n >> m >> k;
  for (int i = 0; i < n; i++) cin >> a[i];
  sort(a, a + n, greater<int>());
  int cnt = k;
  int i = 0;
  for (i = 0; i < n && cnt > 0; i++) {
    if (cnt >= m) break;
    cnt += a[i] - 1;
  }
  if (cnt < m)
    cout << -1 << endl;
  else
    cout << i << endl;
  return 0;
}
