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