source_code: import java.util.Scanner;
  import java.io.OutputStream;
  import java.io.IOException;
  import java.util.Arrays;
  import java.io.PrintWriter;
  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;
  		Scanner in = new Scanner(inputStream);
  		PrintWriter out = new PrintWriter(outputStream);
  		TaskA solver = new TaskA();
  		solver.solve(1, in, out);
  		out.close();
  	}
  }
  
  class TaskA {
  	public void solve(int testNumber, Scanner in, PrintWriter out) {
  		int n = in.nextInt();
  		int m = in.nextInt();
  		int k = in.nextInt();
  		int[] fs = IOUtils.readIntArray(in, n);
  		Arrays.sort(fs);
  		int ptr = fs.length - 1;
  		int res = 0;
  		while (ptr >= 0 && k < m) {
  			k += fs[ptr--] - 1;
  			res++;
  		}
  		if (k < m) out.println(-1);
  		else out.println(res);
  	}
  }
  
  class IOUtils {
      public static int[] readIntArray(Scanner in, int size) {
          int[] array = new int[size];
          for (int i = 0; i < size; i++)
              array[i] = in.nextInt();
          return array;
      }
  
      }
  
  