source_code: import java.io.OutputStream;
  import java.io.IOException;
  import java.io.OutputStreamWriter;
  import java.io.PrintWriter;
  import java.util.Arrays;
  import java.io.BufferedWriter;
  import java.util.InputMismatchException;
  import java.io.Writer;
  import java.io.InputStream;
  
  /**
   * Built using CHelper plug-in
   * Actual solution is at the top
   * @author BSRK Aditya (bsrkaditya@gmail.com)
   */
  public class Main {
  	public static void main(String[] args) {
  		InputStream inputStream = System.in;
  		OutputStream outputStream = System.out;
  		InputReader in = new InputReader(inputStream);
  		OutputWriter out = new OutputWriter(outputStream);
  		TaskA solver = new TaskA();
  		solver.solve(1, in, out);
  		out.close();
  	}
  }
  
  class TaskA {
      public void solve(int testNumber, InputReader in, OutputWriter out) {
          int n = in.readInt();
          int m = in.readInt();
          int k = in.readInt();
  
  
          int [] filters = new int[n];
          for(int i = 0; i < n; ++i) filters[i] = in.readInt();
  
          Arrays.sort(filters);
  
          int nS = 0, tN = k;
  
          while(tN < m && nS < n) {
              tN += filters[n-1-nS] - 1;
              nS++;
          }
  
          if(tN >= m) out.printLine(nS);
          else out.printLine(-1);
      }
  }
  
  class InputReader {
  
      private InputStream stream;
      private byte[] buf = new byte[1024];
      private int curChar;
      private int numChars;
      private SpaceCharFilter filter;
  
      public InputReader(InputStream stream) {
          this.stream = stream;
      }
  
      public int read() {
          if (numChars == -1)
              throw new InputMismatchException();
          if (curChar >= numChars) {
              curChar = 0;
              try {
                  numChars = stream.read(buf);
              } catch (IOException e) {
                  throw new InputMismatchException();
              }
              if (numChars <= 0)
                  return -1;
          }
          return buf[curChar++];
      }
  
  
      public int readInt() {
          int c = read();
          while (isSpaceChar(c))
              c = read();
          int sgn = 1;
          if (c == '-') {
              sgn = -1;
              c = read();
          }
          int res = 0;
          do {
              if (c < '0' || c > '9')
                  throw new InputMismatchException();
              res *= 10;
              res += c - '0';
              c = read();
          } while (!isSpaceChar(c));
          return res * sgn;
      }
  
      public boolean isSpaceChar(int c) {
          if (filter != null)
              return filter.isSpaceChar(c);
          return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
      }
  
      public interface SpaceCharFilter {
          public boolean isSpaceChar(int ch);
      }
  }
  
  class OutputWriter {
      private final PrintWriter writer;
  
      public OutputWriter(OutputStream outputStream) {
          writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
      }
  
      public OutputWriter(Writer writer) {
          this.writer = new PrintWriter(writer);
      }
  
      public void print(Object...objects) {
          for (int i = 0; i < objects.length; i++) {
              if (i != 0)
                  writer.print(' ');
              writer.print(objects[i]);
          }
      }
  
      public void printLine(Object...objects) {
          print(objects);
          writer.println();
      }
  
      public void close() {
          writer.close();
      }
  
  }
  
  