#include <bits/stdc++.h>
using namespace std;
int a[1001];
int n, k, m;
void solve() {
  int i, x, dem;
  sort(a, a + n);
  dem = 0;
  for (i = n - 1; i >= 0; i--) {
    if (k >= m) break;
    k += a[i] - 1;
    dem++;
  }
  if (k < m)
    cout << -1 << endl;
  else
    cout << dem << endl;
}
void input() {
  int i;
  while (cin >> n >> m >> k) {
    for (i = 0; i < n; i++) cin >> a[i];
    solve();
  }
}
int main() {
  input();
  return 0;
}
