#include <bits/stdc++.h>
using namespace std;
int n, m, k, a[56], br;
int main() {
  cin >> n >> m >> k;
  int i;
  for (i = 0; i < n; i++) cin >> a[i];
  sort(a, a + n);
  reverse(a, a + n);
  if (k >= m) {
    cout << 0 << endl;
    return 0;
  } else
    m -= (k - 1);
  for (i = 0; i < n; i++) {
    if (m - a[i] <= 0) {
      br++;
      cout << br << endl;
      return 0;
    } else {
      m -= a[i] - 1;
      br++;
    }
  }
  cout << -1 << endl;
  return 0;
}
