source_code: import java.util.*;
  import java.io.*;
  
  public class Main {
      
      public static void main(String[] args) throws Exception {
          Scanner in = new Scanner(System.in);
          PrintWriter out = new PrintWriter(System.out);
          
          int n = in.nextInt(), m = in.nextInt(), k = in.nextInt();
          int[] a = new int[n];
          for (int i = 0; i < n; i++) a[i] = in.nextInt();
          Arrays.sort(a);
          int ans = 0, r = k, p = n-1;
          while (r < m && p >= 0) {
              r = r - 1 + a[p];
              p--;
              ans++;
          }
          if (r < m) out.println("-1");
          else out.println(ans);
          
          out.flush();
      }
      
  }