source_code: import java.io.InputStreamReader;
  import java.io.IOException;
  import java.util.Arrays;
  import java.io.BufferedReader;
  import java.io.OutputStream;
  import java.io.PrintWriter;
  import java.util.StringTokenizer;
  import java.io.InputStream;
  
  /**
   * Built using CHelper plug-in
   * Actual solution is at the top
   */
  public class Main {
      public static void main(String[] args) {
          InputStream inputStream = System.in;
          OutputStream outputStream = System.out;
          InputReader in = new InputReader(inputStream);
          PrintWriter out = new PrintWriter(outputStream);
          TaskA solver = new TaskA();
          solver.solve(1, in, out);
          out.close();
      }
  }
  
  class TaskA {
      public void solve(int testNumber, InputReader in, PrintWriter out) {
          int n = in.nextInt();
          int m = in.nextInt();
          int k = in.nextInt();
          int[] a = new int[n];
          for (int i = 0; i < n; i++)
              a[i] = in.nextInt();
          Arrays.sort(a);
          if (k >= m) {
              out.println(0);
              return;
          }
          for (int i = 1; i <= n; i++) {
              int sockets = k - 1;
              for (int j = 0; j < i; j++)
                  sockets += a[n - j - 1];
              sockets -= i - 1;
              if (sockets >= m) {
                  out.println(i);
                  return;
              }
          }
          out.println(-1);
      }
  }
  
  class InputReader {
      private BufferedReader reader;
      private StringTokenizer tokenizer;
  
      public InputReader(InputStream stream) {
          reader = new BufferedReader(new InputStreamReader(stream));
          tokenizer = null;
      }
  
      public int nextInt() {
          return Integer.parseInt(next());
      }
  
      public String next() {
          while (tokenizer == null || !tokenizer.hasMoreTokens()) {
              try {
                  tokenizer = new StringTokenizer(reader.readLine());
              } catch (IOException e) {
                  throw new RuntimeException(e);
              }
          }
          return tokenizer.nextToken();
      }
  }
  