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