#include <bits/stdc++.h>
using namespace std;
int a[100];
int main() {
  int n, m, k;
  cin >> n >> m >> k;
  for (int i = 0; i < n; i++) cin >> a[i];
  sort(a, a + n);
  reverse(a, a + n);
  int i;
  for (i = 0; i < n && k < m; i++) k += a[i] - 1;
  if (k < m)
    cout << -1 << endl;
  else
    cout << i << endl;
  return 0;
}
