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