Error: CS0246 Can't access Player Health Script

I trying trying to access the player health script and I am getting an error . The type or namespace name `CharacterHealth' could not be found. Are you missing a using directive or an assembly reference?

Here is my script :

using UnityEngine; using System.Collections;

public class attack1 : MonoBehaviour { public GameObject player; public GameObject bear; public float distance; private CharacterHealth CharacterHealthScript;

 // Use this for initialization
 void Start () {
 

 
 
 }
 
 // Update is called once per frame
 void Update () {
 player = GameObject.FindWithTag("Player");
 bear = GameObject.Find("bear");
 distance = Vector3.Distance(player.transform.position, bear.transform.position);
 
 if (distance <= 3)
 {    
     GameObject Player = GameObject.FindWithTag("Player");
     CharacterHealthScript = Player.GetComponent<Characterhealth>();
     Characterhealth.Max_Health -= 5f;
     GetComponent<Animation>().CrossFadeQueued("move" , 0.3f, QueueMode.PlayNow);
     GetComponent<Animation>().CrossFade("attack");
 }
 
 else if (distance < 15 && distance > 3.0f){
     GetComponent<Animation>().CrossFadeQueued("attack", 0.3f, QueueMode.PlayNow);
     GetComponent<Animation>().CrossFade("move");
     transform.LookAt(player.transform.position);

     
     
 }
  else 
 

 
 { 
 
 }
 
 }
 
 }

sing UnityEngine;

namespace Opsive.ThirdPersonController { ///

/// Extends the health component by allowing the character to take fall damage. The amount of damage is specified by a curve. /// public class CharacterHealth : Health { [Tooltip("Should fall damage be applied?")] [SerializeField] private bool m_UseFallDamage; [Tooltip("The minimum height that the character has to fall in order for any damage to be applied")] [SerializeField] private float m_MinFallDamageHeight; [Tooltip("A fall greater than this value is an instant death")] [SerializeField] private float m_DeathHeight; [Tooltip("The amount of damage to apply when the player falls by the minimum fall damage height")] [SerializeField] private float m_MinFallDamage; [Tooltip("The amount of damage to apply when the player falls just less than the death height")] [SerializeField] private float m_MaxFallDamage; [Tooltip("A curve specifying the amount of damage to apply if the character falls between the min and max fall damage values")] [SerializeField] private AnimationCurve m_DamageCurve = AnimationCurve.Linear(0, 0, 1, 1);

     /// <summary>
     /// Register for any events that the health should be aware of.
     /// </summary>
     private void OnEnable()
     {
         if (m_UseFallDamage) {
             EventHandler.RegisterEvent<float>(m_GameObject, "OnControllerLand", OnCharacterLand);
         }
     }

     /// <summary>
     /// Unregister for any events that the health was registered for.
     /// </summary>
     private void OnDisable()
     {
         if (m_UseFallDamage) {
             EventHandler.UnregisterEvent<float>(m_GameObject, "OnControllerLand", OnCharacterLand);
         }
     }

     /// <summary>
     /// The character has landed after falling a spcified amount. Determine if any damage should be taken.
     /// </summary>
     /// <param name="fallHeight"></param>
     private void OnCharacterLand(float fallHeight)
     {
         // Return immediately if the fall height is less than the minimum height that the character has to fall in order to start taking damage.
         if (fallHeight < m_MinFallDamageHeight) {
             return;
         }

         var damageAmount = 0f;
         // The fall was too great, specify an infinite amount of damage.
         if (fallHeight >= m_DeathHeight) {
             damageAmount = Mathf.Infinity;
         } else {
             // The fall was somewhere in between the min and max fall height. Use the damage curve to determine how much damage to apply.
             var normalizedHeight = (fallHeight - m_MinFallDamageHeight) / (m_DeathHeight - m_MinFallDamageHeight);
             var damageAmountMultiplier = m_DamageCurve.Evaluate(normalizedHeight);
             damageAmount = m_MinFallDamage + damageAmountMultiplier * (m_MaxFallDamage - m_MinFallDamage);
         }

         // Apply the damage.
         Damage(damageAmount, m_Transform.position, Vector3.zero);
     }
 }

}