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