source_code: import java.util.Arrays;
  import java.util.InputMismatchException;
  import java.io.*;
  
  /**
   * Generated by Contest helper plug-in
   * Actual solution is at the bottom
   */
  public class Main {
      public static void main(String[] args) {
          InputReader in = new StreamInputReader(System.in);
          PrintWriter out = new PrintWriter(System.out);
          run(in, out);
      }
  
      public static void run(InputReader in, PrintWriter out) {
          Solver solver = new TaskB();
          solver.solve(1, in, out);
          Exit.exit(in, out);
      }
  }
  
  abstract class InputReader {
      private boolean finished = false;
  
      public abstract int read();
  
      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 String readString() {
          int c = read();
          while (isSpaceChar(c))
              c = read();
          StringBuffer res = new StringBuffer();
          do {
              res.appendCodePoint(c);
              c = read();
          } while (!isSpaceChar(c));
          return res.toString();
      }
  
      private boolean isSpaceChar(int c) {
          return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
      }
  
      public void setFinished(boolean finished) {
          this.finished = finished;
      }
  
      public abstract void close();
  }
  
  class StreamInputReader extends InputReader {
      private InputStream stream;
      private byte[] buf = new byte[1024];
      private int curChar, numChars;
  
      public StreamInputReader(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 void close() {
          try {
              stream.close();
          } catch (IOException ignored) {
          }
      }
  }
  
  class Exit {
      private Exit() {
      }
  
      public static void exit(InputReader in, PrintWriter out) {
          in.setFinished(true);
          in.close();
          out.close();
      }
  }
  
  interface Solver {
      public void solve(int testNumber, InputReader in, PrintWriter out);
  }
  
  class TaskB implements Solver 
  {
      public void solve(int testNumber, InputReader in, PrintWriter out) 
      {
          int n = in.readInt();
          int m = in.readInt();
          int k = in.readInt();
          int[] a = new int[n];
          for(int i=0;i<n;i++) a[i] = in.readInt();
          Arrays.sort(a);
          if(k>=m)
          {
              out.println(0);
          }
          else
          {
              for(int i=n-1;i>=0;i--)
              {
                  k += (a[i]-1);
                  if(k>=m) 
                  {
                      out.println(n-i);
                      return;
                  }
              }
              if(k<m) out.println(-1);
          }
      }
  }
  