How to make 2 collectibles can only be reached by jumping in roll a ball tutorial

Hello everyone, I am new to unity community and codding. I already finished the roll a ball tutorial and now I am working on develop the game into two local players which have jumping functions. I already added jump keys for the players, but how to write a script to make that 2 collectible can only be reached by jumping? I am trapped here and hope to get some suggestions. Thank you very much!

here is part of my code:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.UI;
 
 public class Playercontroller : MonoBehaviour
 {
 
     public float speed;
     public Text countText;
 
     public KeyCode left;
     public KeyCode right;
     public KeyCode up;
     public KeyCode down;
     public KeyCode jump;
 
     public bool isGrounded;
     public float jumpHeight;
     public float GravityStrength;
     using System.Collections;
     using System.Collections.Generic;
     using UnityEngine;
     using UnityEngine.UI;
     
     public class Playercontroller : MonoBehaviour
     {
     
         public float speed;
         public Text countText;
         
     
         public KeyCode left;
         public KeyCode right;
         public KeyCode up;
         public KeyCode down;
         public KeyCode jump;
     
         public bool isGrounded;
         public float jumpHeight;
         public float GravityStrength;
     
         private Rigidbody rb;
         private int count;
     
         void Start()
         {
             rb = GetComponent<Rigidbody>();
             isGrounded = true;
             count = 0;
             SetCountText ();
         }
     
         void FixedUpdate()
         {
             Vector3 gravityS = new Vector3(0, GravityStrength,0);
             Physics.gravity = gravityS;
           
             if(Input.GetKey(jump) && isGrounded == true)
             {
                 Jump();
             }
         }
     
         void Jump()
         {
             rb.AddForce(new Vector3(0, jumpHeight, 0));
             isGrounded = false;
         }
     
         void OnCollisionEnter()
         {
             isGrounded = true;
         }
     
         void OnTriggerEnter(Collider other)
         {
             if (other.gameObject.CompareTag("Pick Up"))
             {
                 other.gameObject.SetActive (false);
                 count = count + 1;
                 SetCountText();
             }
         }
     
         }
     }
     
 
  void Start()
     {
         rb = GetComponent<Rigidbody>();
         isGrounded = true;
         count = 0;
         SetCountText ();
     }
 
 
 
     {
         rb.AddForce(new Vector3(0, jumpHeight, 0));
         isGrounded = false;
     }
 
     void OnCollisionEnter()
     {
         isGrounded = true;
     }
 
     void OnTriggerEnter(Collider other)
     {
         if (other.gameObject.CompareTag("Pick Up"))
         {
             other.gameObject.SetActive (false);
             count = count + 1;
             SetCountText();
         }
     }