double jump - max once

Hi, I wrote script for double jumping and I noticed I can jump how many times I want. How can I make double jump once, for just two jumping and that's all? Here's my script (include few lines of moving but don't pay attention on it):

 using UnityEngine;
 using System.Collections;
 
 [RequireComponent(typeof(Rigidbody))]
 
 public class Moving : MonoBehaviour {
 
     bool isOnGround;
     public Transform groundCheck;
     public LayerMask whatIsTheGround;
     float groundSphere = 0.3f;
 
     bool isDoubleJumpAvailable;
 
     public float jumpForce;
     public float secondJump;
     public float jumpForceHold;
     public float maxJumpTime;
     float MaxJumpTimeInternal;
 
     public Rigidbody rBody;
     public float ballSpeed = 10f;
 
     void Start()
     {
         rBody = GetComponent<Rigidbody>();
     }
 
     void Update()
     {
 
         float v = Input.GetAxis("Vertical");
         float h = Input.GetAxis("Horizontal");
         rBody.AddForce(new Vector3(h, 0, v) * ballSpeed);
 
         if (isOnGround && Input.GetButtonDown("Jump"))
         {
             GetComponent<Rigidbody>().AddForce(new Vector3(0, jumpForce, 0));
             MaxJumpTimeInternal = maxJumpTime;
             isDoubleJumpAvailable = true;
 
         }
 
         if (Input.GetButton("Jump") && GetComponent<Rigidbody>().velocity.y > -1 && MaxJumpTimeInternal > 0)
         {
             GetComponent<Rigidbody>().AddForce(new Vector3(0, jumpForceHold, 0));
             MaxJumpTimeInternal = MaxJumpTimeInternal - 1;
         }
 
         if (!isOnGround && isDoubleJumpAvailable && Input.GetButtonDown("Jump"))
         {
             isDoubleJumpAvailable = false;
             MaxJumpTimeInternal = maxJumpTime / 2;
             GetComponent<Rigidbody>().Sleep();
             GetComponent<Rigidbody>().AddForce(new Vector3(0, secondJump, 0));
         }
 
     }
 
     void FixedUpdate()
     {
         isOnGround = Physics.OverlapSphere(groundCheck.position, groundSphere, whatIsTheGround).Length > 0;
 
     }
 }