CS1525 : Unexpected symbol 'hbLength'

Hi i was making a health bar script and i got this error when i was done it would be really nice if someone could just help me out on this one and solve my problem please script has been a pain for me

c#

 using UnityEngine;
 using System.Collections;
 
 public class playerhealth : MonoBehaviour {
 
     public int currentHealth;
     public int maximumHealth = 100;
 
     public float hbLength;
 
     // Use this for initialization
     void Start () {
         currentHealth = maximumHealth
         
         hbLength = Screen.width / 2;
     
     }
     
     // Update is called once per frame
     void Update () {
         ChangeHealth (0);
     
     }
         void OnGUI () {
         GUI.Box (new Rect(10, 10, hbLength, 30), currentHealth + " / " + maximumHealth);
     }
 
        public void ChangeHealth (int health) (
         currentHealth += health;
        
        hbLength = (Screen.width / 2) * (currentHealth / (float)maximumHealth);
     }
 }