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