How can I make a collider that gives me stat up to stop giving me it?

Hi, i'm begginer in unity2D and I want to make a collider that, when you hit it, it gives you "strength", I have already made it but when I hit this collider, the strenght increase never stops (just by hitting it one time). How can I make the collider to give just +1 strenght? Thanks. (Sorry about my english, hope you undestand it :P )

This is part of the script assigned to the collider.

     void OnTriggerEnter2D(Collider2D col)
     {
         tocat = true;
         atac1.enabled = false;
     }
     void OnTriggerExit2D(Collider2D col)
     {
         tocat = false;
         Debug.Log("hola");
     }
     
 }

And here is the status increase script.

 public class Texto : MonoBehaviour {
     public GameObject colision;
     public Atacc atacke;
     public Text text;
     public int atac;
     
     // Use this for initialization
     void Start () {
         atacke = colision.GetComponent<Atacc>();
         text = GetComponent<Text>();
         
     }
     
     // Update is called once per frame
     void Update () {
         text.text = " " + atac;
         if (atacke.tocat == true) ++atac;
     }
 }