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