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