#include <bits/stdc++.h>
using namespace std;
int n, m, k, a[10001];
int main() {
  cin >> n >> m >> k;
  for (int i = 1; i <= n; i++) cin >> a[i];
  sort(a + 1, a + n + 1);
  if (m <= k) {
    cout << 0;
    return 0;
  }
  for (int i = n; i >= 1; i--) {
    k += a[i] - 1;
    if (m <= k) {
      cout << n - i + 1;
      return 0;
    }
  }
  cout << -1;
  return 0;
}
