source_code: import java.io.*;
  import java.util.*;
  import java.lang.*;
  
  public class Main {
  
    public static void main(String[] args) {
      Scanner cin=new Scanner(new BufferedInputStream(System.in));
      
      int n=cin.nextInt(),
          m=cin.nextInt(),
          k=cin.nextInt();
      int[] a=new int[51];
      
      for (int i=0;i<n;i++) {
        a[i]=-cin.nextInt();
      }
      Arrays.sort(a);
      
      if (m<=k) {
          System.out.println(0);
          return;
      }
      for (int i=0;i<Math.min(k,n);i++) {
        m+=a[i];
        if (m-(k-1-i)<=0) {
          System.out.println(i+1);
          return;
        }
      }
      for (int i=k;i<n;i++) {
        m+=a[i]+1;
        if (m<=0) {
          System.out.println(i+1);
          return;
        }
      }
      System.out.println(-1);
      
      cin.close();
    }
  
  }