source_code: import java.io.IOException;
  import java.io.OutputStreamWriter;
  import java.util.Arrays;
  import java.io.BufferedWriter;
  import java.util.InputMismatchException;
  import java.io.PrintStream;
  import java.io.OutputStream;
  import java.io.PrintWriter;
  import java.io.Writer;
  import java.math.BigInteger;
  import java.io.InputStream;
  
  /**
   * Built using CHelper plug-in
   * Actual solution is at the top
   * @author coderbd
   */
  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 m, n, k;
          n = in.readInt();
          m = in.readInt();
          k = in.readInt();
          int[] a = new int[n];
          for (int i = 0; i < n; i++)
              a[i] = in.readInt() - 1;
          Arrays.sort(a);
          int ans = -1;
          if (k >= m)
              ans = 0;
          else for (int i = 0; i < n; i++) {
              k += a[n-i-1];
              if (k >= m) {
                  ans = i + 1;
                  break;
              }
          }
          System.out.println(ans);
      }
  }
  
  class InputReader {
      private boolean finished = false;
  
      private InputStream stream;
      private byte[] buf = new byte[1024];
      private int curChar;
      private int numChars;
  
      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 peek() {
          if (numChars == -1)
              return -1;
          if (curChar >= numChars) {
              curChar = 0;
              try {
                  numChars = stream.read(buf);
              }
              catch (IOException e) {
                  return -1;
              }
              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 long readLong() {
          int c = read();
          while (isSpaceChar(c))
              c = read();
          int sgn = 1;
          if (c == '-') {
              sgn = -1;
              c = read();
          }
          long res = 0L;
          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();
      }
  
      public static boolean isSpaceChar(int c) {
          return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
      }
  
      private String readLine0() {
          StringBuffer buf = new StringBuffer();
          int c = read();
          while (c != '\n' && c != -1) {
              if (c != '\r')
                  buf.appendCodePoint(c);
              c = read();
          }
          return buf.toString();
      }
  
      public String readLine() {
          String s = readLine0();
          while (s.trim().length() == 0)
              s = readLine0();
          return s;
      }
  
      public String readLine(boolean ignoreEmptyLines) {
          if (ignoreEmptyLines)
              return readLine();
          else
              return readLine0();
      }
  
      public BigInteger readBigInteger() {
          try {
              return new BigInteger(readString());
          }
          catch (NumberFormatException e) {
              throw new InputMismatchException();
          }
      }
  
      public char readCharacter() {
          int c = read();
          while (isSpaceChar(c))
              c = read();
          return (char) c;
      }
  
      public double readDouble() {
          int c = read();
          while (isSpaceChar(c))
              c = read();
          int sgn = 1;
          if (c == '-') {
              sgn = -1;
              c = read();
          }
          double res = 0;
          while (!isSpaceChar(c) && c != '.') {
              if (c == 'e' || c == 'E')
                  return res * Math.pow(10, readInt());
              if (c < '0' || c > '9')
                  throw new InputMismatchException();
              res *= 10;
              res += c - '0';
              c = read();
          }
          if (c == '.') {
              c = read();
              double m = 1;
              while (!isSpaceChar(c)) {
                  if (c == 'e' || c == 'E')
                      return res * Math.pow(10, readInt());
                  if (c < '0' || c > '9')
                      throw new InputMismatchException();
                  m *= 10;
                  res += (c - '0') * m;
                  c = read();
              }
          }
          return res * sgn;
      }
  
      public boolean isExhausted() {
          int value;
          while (isSpaceChar(value = peek()) && value != -1)
              read();
          return value == -1;
      }
  
      public String next() {
          return readString();
      }
  }
  
  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 printLine(char[] array) {
          writer.print(array);
      }
  
      public void printFormat(String format, Object...objects) {
          writer.printf(format, objects);
      }
  
      public void close() {
          writer.close();
      }
  
      public void flush() {
          writer.flush();
      }
  }
  
  