A namespace can only contain types and namespace declarations

Hey, guys. So I'm fairly new to Unity and to the C# language and am getting "error CS0116: A namespace can only contain types and namespace declarations" on line 63,14 which is this piece of code:

     void Update () {
         if(Input.GetKeyDown(KeyCode.Tab))
         {
             TargetEnemy();
         }
     }

I'm sure it's a simple solution, I just can't seem to figure it out! Here's the full code, if it's needed?

 enter code hereusing UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 
 public class Targetting : MonoBehaviour {
 public List<Transform> targets;
 private Transform myTransform;
 public Transform selectedTarget;
 
 // Use this for initialization
     void Start () {
     targets = new List<Transform>();
     selectedTarget = null;
     AddAllEnemies();
     myTransform = transform;
     }
     public void AddAllEnemies()
     {
     GameObject[] go = GameObject.FindGameObjectsWithTag("Enemy");
         foreach(GameObject enemy in go)
             AddTarget(enemy.transform);
     }
     public void AddTarget(Transform enemy) {
         targets.Add(enemy);
     }
     private void SortTargetsByDistance()
     {
     targets.Sort(delegate(Transform t1, Transform t2){
         return(Vector3.Distance(t1.position, myTransform.position).CompareTo(Vector3.Distance(t2.position, myTransform.position)));
         });
     }
 
     private void TargetEnemy()
     {
     if(selectedTarget == null){
     SortTargetsByDistance();
     selectedTarget = targets[0];
     }
     else{
         int index = targets.IndexOf(selectedTarget);
             if(index < targets.Count - 1){
             index++;
         }
     else{
         index = 0;
         }
     DeselectTarget();
     selectedTarget = targets[index];
     SelectTarget();
     }
 }
     private void SelectTarget(){
     selectedTarget.renderer.material.color = Color.red;
 }
     
     private void DeselectTarget(){
         selectedTarget.renderer.material.color = Color.blue;
     selectedTarget = null;
     }
 }
 // Update is called once per frame
 
     void Update () {
         if(Input.GetKeyDown(KeyCode.Tab))
         {
             TargetEnemy();
         }
 }
 

Thanks in advance.