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