Infinite value add

I have a code where you collect a chest and it disappears when pressing "E" when entering the chest's trigger, and I wanted to keep in a variable how many chests you collect. It works good, but after you collect the chest, if you keep pressing "E", the number of chests keeps going up. I need some help to fix this. Here is the code:

 public int Chests = 0;
 private bool pickUpAllowed;
 public GameObject gameObject;

 private void Start()
 {
     pickUpText.gameObject.SetActive(false);
 }

 // Update is called once per frame
 private void Update()
 {
     if (pickUpAllowed && Input.GetKeyDown(KeyCode.E))
     {
         PickUp();
     }
 }

 private void OnTriggerEnter(Collider collision)
 {
     Debug.Log($"Collided with {collision.gameObject.name} tagged {collision.gameObject.tag}", collision.gameObject);
 
     if (collision.gameObject.tag == "Chest")
     {
         pickUpText.gameObject.SetActive(true);
         pickUpAllowed = true;
     }
 }

 private void OnTriggerExit(Collider collision)
 {
     Debug.Log($"Exited Collided with {collision.gameObject.name} tagged {collision.gameObject.tag}", collision.gameObject);
     if (collision.gameObject.tag == "Chest")
     {
         pickUpText.gameObject.SetActive(false);
         pickUpAllowed = false;
     }
 }

 private void PickUp()
 {
     Destroy(gameObject);
     Chests++;
 }

}