source_code: import java.util.Arrays;
  import java.util.Scanner;
  
  public class Main2 {
  	
      public static void main(String args[]){
          Scanner input = new Scanner(System.in);
          int n = input.nextInt();
          int m = input.nextInt();
          int k = input.nextInt();
          int[] num = new int[n];
          for(int i = 0 ; i < n ; i++){
          	num[i] = input.nextInt();
          }
          
          System.out.println(str(n,m,k,num));
      }
  
  	static int str(int n,int m,int k,int[] num){
  		Arrays.sort(num);
  		int total = k;
  		int count = 0;
  		while(k < m){
  			if(count == num.length)return -1;
  			k += num[num.length-count-1]-1;
  			count++;
  		}
  		return count;
  	}
  	
  }