#include <bits/stdc++.h>
using namespace std;
int main() {
  long long x, y, n, m, k;
  int i, j, a[55];
  bool f = 0;
  cin >> n >> m >> k;
  for (i = 0; i < n; i++) cin >> a[i];
  sort(a + 0, a + n);
  if (k >= m) {
    cout << 0 << endl;
    f = 1;
  } else
    for (i = n - 1, x = 0; i >= 0 && k > 0; i--) {
      if (i < (n - 1))
        x += (a[i] - 1);
      else
        x += a[i];
      if ((x + k - 1) >= m) {
        cout << (n - i) << endl;
        f = 1;
        break;
      }
    }
  if (f == 0) cout << -1 << endl;
  return 0;
}
