BCE0023: No appropriate version of 'UnityEngine.Component.GetComponent' for the argument list '(UnityEngine.TextMesh)' was found.

New to programming so sorry if this is simple. I am trying to use a textmesh code to edit a 3D text in game. basically what i have done is assigned an invisible integer as its health, that integer is sent to a string so i can use that string to edit the 3D text (hopefully that makes sense) Here is my code.

 #pragma strict
 var Militia : GameObject;
 var hp : GameObject;
 var cube : GameObject;
 var trigger : GameObject;
 var red_hp : int = 100;
 var red_range : boolean = false;
 var hp_value : String ="";
 var hp_real : TextMesh;
 function Start () 
 {
     Militia.SetActive(false);
     hp.SetActive(false);
     red_range = false;
 }
 
 function Update () 
 {
     if(Input.GetKeyUp(KeyCode.F))
     {
         if(red_range == true)
         {
             red_hp = red_hp - 25;
             hp_value= red_hp.ToString();
             GetComponent(hp_real).text = hp_value; << Error is here
             if (red_hp <=0)
             {
                 Destroy (cube);
                 Destroy (Militia);
                 Destroy(hp);
             }
         }
     }
 }
 
 function OnTriggerEnter (trigger : Collider)
     {  
         Militia.SetActive(true);
         hp.SetActive(true);
         red_range = true;
     }
 function OnTriggerExit (trigger : Collider)
 {  
     if (red_hp >=0)
     {
         Militia.SetActive(false);
         hp.SetActive(false);
         red_range = false;
     }
 }

Any help will be appreciated

Thanks