#include <bits/stdc++.h>
using namespace std;
void solve() {
  long long n, m, k, i, count = 0;
  cin >> n >> m >> k;
  if (m <= k) {
    cout << "0";
    return;
  }
  vector<long long> a(n);
  for (i = 0; i < n; i++) cin >> a[i];
  sort(a.begin(), a.end());
  if (a[n - 1] >= m) {
    cout << "1";
    return;
  }
  for (i = n - 1; i >= 0; i--) {
    count++;
    m -= a[i];
    m++;
    if (m <= k) {
      cout << count;
      return;
    }
    if (i == 0 && m != 0) {
      cout << "-1";
      return;
    }
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  ;
  long long t = 1;
  while (t--) {
    solve();
    cout << "\n";
  }
  return 0;
}
