source_code: import java.io.*;
  import java.util.*;
  public class a{
      static int a;
      static Scanner sc = new Scanner(System.in);
      public static void main(String[] args) throws IOException{
          int n = sc.nextInt();
          int p = n;
          int m = sc.nextInt();
          int k = sc.nextInt();
          int a[] = new int[n];
          for (int i = 0; i < n; i++)
          {
              a[i] = sc.nextInt() - 1;
          }
          Arrays.sort(a);
          int j =0;
          for(int i=0; i<n; i++){
              if(m > k){
                  k = k + a[n-i-1];
                  j++;
              }
          }
          if(m > k)
              System.out.println(-1);
          else
              System.out.println(j);
      }
      
  }